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151 Cards in this Set
- Front
- Back
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Two main grading systems for soft tissue sarcomas:
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1. French Sarcoma Group
- favored system - based on differentiation, mitotic activity, and necrosis 2. NCI |
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The most common primary soft tissue malignancy is ___
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liposarcoma
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Adipocytic tumor occur most often in adults, with two exceptions __ and ___
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1. lipoblastoma
2. some lipomas |
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Lipoblast are not specific for malignancy, they can be seen in ___
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1. pleomorphic lipomas
2. chondroid lipomas 3. lipoblastoma 4. spindle cell lipoma (less often) |
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lipomas are mutiple in __% of patients
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5%
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intramuscular versus intermuscular lipomas
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Intramuscular lipomas:
- in skeletal muscle in a variety of locations - incomplete excision : 20% recur Intermuscular lipoma: - most commonly anterior abdomen Both: mid to late adulthood |
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Fatty infiltration of the subsynovial connective tissue
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lipoma aborescens (villous lipomatous proliferation of synovial membrane)
or (synovial lipoma) - may be a reactive process |
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Lipoma variant include:
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chondrolipoma
myxolipoma osteolipoma fibrolipoma |
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The edge/margin of a intramuscular lipomas is
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well-demarcated or more often infiltrative with adipocytes surrounding atrophic muscle fibers
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The subtype of lipomas is not clinically significant except for:
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infiltrating intramuscular lipomas
- higher local recurrence rate - requires resection of the entire involved muscle or compartment |
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diffuse overgrowth of mature adipose tissue is known as __. Subtypes include:
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lipomatosis
1. diffuse lipomatosis - pt usually < 2yo - +/- macrodactyly - involves large portions of body or limbs 2. pelvic lipomatosis - most common in black males - constipation, urinary freq, perineal pain, back pain 3. symmetric lipomatosis - middle aged men of Mediterranean origin - a/w liver disease and alcohol use - deposition of at in upper body (mostly neck) 4. steroid lipomatosis - exogenous or endogenous steroid - deposition of fat in face, sternal area, upper mid back (buffalo hump) |
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Histologically, the fat seen in lipomatosis is __
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normal-appearing mature fat
- the only abnormalities are the site of involvement and the distribution of the fat |
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Lipomatosis of nerve: the __ is infiltrated by __ and __.
AKA: |
(contrast to diffuse lipomatosis)
1. epineurium 2. fibrous and adipose tissue AKA: neural fibrolipoma, fibrolipomatous hamartoma, perineural fibroma |
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neural fibrolipoma: usually first recognized at _ or in __
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birth or early childhood
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neural fibrolipoma: is a hamartoma of the nerve sheath because the __
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constituent tissues are normal components of the epineurium
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In some cases of neural fibrolipoma, there is associated __
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macrodactyly due to lipohypertrophy (25% cases)
- enlargement of soft tissue and bone effects the digits of the affected nerve |
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neural fibrolipoma: most commonly effects __
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median nerve, followed by ulnar nerve
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neural fibrolipoma: is typically a __ event
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sporadic
- not associated with any syndrome or known hereditary predisposition |
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neural fibrolipoma: histologically
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- fatty infiltration w/ admixed fibrous tissue into the epinerual and perineural tissue
- concentric perineural fibrosis (about individual nerve bundles) |
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neural fibrolipoma: onset is in ___, but presentation to the physician is usually in __
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- early childhood/birth
- early adulthood |
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superficial lipomas > 10 cm often turn out to be __
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Atypical lipomatous tumors
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dermal lipoma versus nevus lipomatosus superficialis
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dermal lipoma:
- common, solitary lesion - most likely a fibroepithelial polyp in which the adipose tissue predominates nevus lipomatosus superficialis - used ONLY when such lesions are mutliple and clustered about the lower limb girdle - considered a hamartoma |
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intramuscular lipomas present in __ as __
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mid adulthood
slow growing, deep-seated mass in the thigh or trunk |
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intramuscular lipoma versus intramuscular hemangioma (angioma)
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intramuscular lipoma:
- mid-adulthood - vessels are scarce and capillary-sized - less frequent recurrences (20% w/ incomplete excision) intramuscular angioma: - younger(adolescent - young adult) - prominent vascular component - high probability of recurrence with incomplete excision (30-50%) - slow growing, often PAINFUL, especially after exercise Note: angioma: because most are a mix of capillary, small artery, venous, and lymphatic-like spaces |
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__% of intramuscular lipomas are well-circumscribed and non-infiltrative; these __ recur
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10%
do not recur |
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diagnosis of intermuscular lipomas requires __ and/or__
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radiologic and/or intraoperative findings
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Multiple symmetric lipomatosis is the __ common type of lipomatosis. It mainly involves the ____. It is associated with ___
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- type of diffuse lipomatosis
- most common type of lipomatosis - neck and shoulder areas - a/w peripheral neuropathy, alcoholism, and hyperlipidemia |
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Liopmatosis mainly effects __
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adult men
(except diffuse lipomatosis: <2 yo) |
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Lipoblastoma (aka__) is most commonly seen in the __ years of life
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infantile lipoma
first 3 years of life |
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lipoblastoma most commonly occur in the _
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extremities
- other sites: mediastinum, trunk, retroperitoneum, head&neck, within various organs (lung, heart, parotid gland) |
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Lipoblastoma versus lipoblastomatosis
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lipoblastoma:
- superficial (limited to subcutis) lipoblastomatosis: - infiltrates deep muscle |
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Lipoblastoma histologically
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- lobulated admix of mature and immature adipocytes
- lipoblasts in various stages of development - number of lipoblasts varies with age - |
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lipoblastomas can have myxoid stroma and a plexiform vascular pattern, mimicking a __
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myxoid liposarcoma
BUT: - myxoid liposarc is rare <10yo - expect to see nuclear atypia - LACK the pronounced lobulated appearance of lipoblastoma |
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lipoblastoma: characteristic cytogenetic finding
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rearrangements involving 8q11-13 (majority of cases)
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lipoblastomas are __ lesions
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benign!
- no mets - no malignant transformation - uncommonly recur (except: lipoblastomatosis has a greater chance of recurrence 9-22%) requiring wide local excision |
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lipoblastomas occur mostly in _
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male children < 3yo
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Histologic features of lipoblastoma
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- lobules of mixed mature and immature adipocytes separated by fibrous septae
- more immature lobules contain primitive mesenchymal cells, lipoblasts, and small capillaries, all in a myxoid background (WITHOUT ATYPIA to distinguish it from a myxoid liposarc) - more mature lobules resemble lipoma with a little more prominent nuclei and variation in adipocyte size - commonly see foci of EMH - may see hibernoma-like foci |
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lipoblastoma can appear very similar to a myxoid liposarcoma
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- mxyoid liposarc in pts 10-30 are typically low grade tumors!
- lipoblastomas are lobulated, have more degress of maturation, lack nuclear atypia - rarely lipoblastomas occur in older children - cytogenetics may be needed - t(12;16) myxoid liposarc - rearrangements involving 8q11-13 (PRAG1 gene) in lipoblastoma |
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angiolipomas are usually <__cm
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<2cm
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angiolipomas consists of two mesenchymal components:
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1. mature adipocytes
2. branching capillary-sized vessels, with fibrin thrombi |
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cellular angiolipomas are those composed of __
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predominantly vascular component
DDX: angiosarcoma or Kaposi sarcoma |
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angiolipomas have a __ karyotype
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normal!!
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Myolipomas consists of two mesenchymal components:
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1. mature adipocytes
2. smooth muscle |
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Myolipoma (aka___) are extremely__
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1. extrauterine lipoleiomyoma
2. rare |
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most myolipomas (extrauterine lipoleiomyomas) occur __
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- deep
- abdominal cavity, retroperitoneum, inguinal areas |
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average size for a myolipoma is ___
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15 cm (big tumors)
Note: smaller lesions are seen in the subcutis |
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in myolipomas, the __ component usually dominates
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smooth muscle component predominates (muscle:fat ratio 2:1)
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myolipomas: histological findings
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- evenly distributed short fascicles of smooth muscle intermixed with fat (sieve-like pattern)
- NO mitoses - NO atypia in the lipomatous component!!! - NO floret cells or lipoblasts - NO large-caliber thick-walled vessels (AML) DDX: - angiomyolipoma - WD liposarcoma with heterologous smooth muscle differentiation!!! |
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chondroid lipoma: DDX
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1. chondroid lipoma
2. myxoid liposarcoma 3. extraskeletal chondrosarcoma |
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chondroid lipoma most commonly occur
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mostly proximal extremity/ limb gridles
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chondroid lipoma are often __-seated tumors, involving __
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deep-seated tumors
involving skeletal muscle and deep fibrous connective tissues |
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chondroid lipoma often present as __, however, in 50% of cases, there is a history of __
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painless mass of variable duration
recent history of enlargement |
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chondroid lipoma: histologic findings
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- hallmark: nests and chords of abundant uni- and multi-vaculated lipoblasts embedded in a prominent myxoid to hyalinized chondroid matrix admixed with variable amounts of mature adipose
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Key findings allowing recognition of a chondroid lipoma
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- admixture of mature adipocytes, lipoblasts with bland nuclei, and hibernoma-like cells
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The Frech Sarcoma Group system gaining favor for gradin STS because of __
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- greater reproducibility
- less patients assigned to intermediate category |
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Single most common type of primary soft tissue malignancy __
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Liposarcaroma (including the atypical lipomatous tumor)
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Majority of adipocytic tumors occur in __hood, except for ___ and ___
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adulthood
exceptions: 1. lipoblastoma 2. occasional lipomas |
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Do lipoblasts = malignancy?
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NO!!
1. Lipoblasts are not seen in every liposaroma: - some WD liposarcoma/Atypical lipomatous tumors - some myxoid liposaromas 2. Lipoblasts can be seen in some benign tumors - pleomorphic lipomas - less often spindle cell lipomas - chondroid lipomas - lipoblastoma |
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Lipomas usually occur in the __ and ___, rarely do they occur in the __ and __
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trunk/ proximal extremity
hands/ feet |
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Lipomas are usually solitary, but __% of patients have multiple lesions
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2-3%
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Rate of recurrence of lipomas should be less than __
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1-2%
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Grossly, most lipomas are ___, thinly ____, and ___
Rarely are the >__cm, if so: |
well-circumscribed
thinly encapsulated lobulated rarely >10cm, if so: should be sample carefully, often turn out to be a atypical lipomatous tumor/ED liposarcoma |
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Lipomas are composed of ___ adipocytes, with minimal variation in ___, and nuclei that are __
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- univacuolated
- cell size - inconspicuous, small compressed to the edge of the cell |
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Foci of adipocytic cells with variable cell size, in an otherwise benign lipoma, may represent __
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- microscopic fat necrosis
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reproducible karyotypic abnormalities involving ___ are seen in subcutaneous lipomas
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12q13-15
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Dermal lipoma, is a common, ___ skin lesion, mainly in ___ (age group), and most likely represents a __.
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- common, pedunculated skin lesion
- young adults - fibroepithelial polyp (skin tag) with a prominent adipose tissue component - hamartomatous lesion |
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If a patient presents with multiple, grouped dermal lipomas, clustered around the ___, the term __ should be used.
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- lower limb girdle
- nevus lipomatosus superficialis |
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Synovial lipomas (aka___) is characterized by ___ collections of __ adipocytes which project, in a ___ fasion, into the joint space. The overlying synovium is often __ and variably __
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- lipoma aborescens
- subsynovial collections of mature adipocytes - villous fashion - hyperplastic synovium - variably inflamed |
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Synovial lipoma usually occurs in ___ (age group), most often affects the ___, and is usually associated with ___
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- adults
- knee - degenerative joint disease |
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Synovial lipoma is most likely a __ process
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reactive
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Intramuscular lipomas differ from usual superificial lipomas
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- poorly circumscribed
- infiltrative - up to 20% (versus <1-2%) chance of recurrence if incompletely excised Note: 10% of intramuscular lipomas are circumscribed, non-infiltrative, and tend NOT to recur |
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Intramuscular lipomas can and should be differentiated from intramuscular ___
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intramuscular angioma(hemangiomas)!!
Intramuscular lipomas: - scarce blood vessels - vessels that are present are usually capillary-sized Intramuscular angioma: - variable amounts of mature fat - more vascular lesions, classified by vessel size: small (capillary, large (cavernous), and most commonly mixed types Intramuscular lipomas are less likely to recur, compared to intramuscular angiomas (up to 20% versus 30-50%) |
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Note: a WD liposarcoma/atypical lipomatous tumor is __ common than an intramuscular lipoma
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more common
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Intermuscular lipomas usually occur in the __
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anterior abdnominal wall
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Lipomatosis is a __ condition characterized by diffuse ___ of __ tissue. It usually affects __
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- rare
- overgrowth - fatty tissue - adult males |
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There are four principle forms of lipomatosis
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1. multiple symmetric lipomatosis
2. asymmetric lipomatosis 3. pelvic lipomatosis 4. mediastinoabdominal lipomatosis |
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Multiple symmetric lipomatosis is the __ form. It affects mainly the ___ and ___ region. Often associated with __, ___, and ___. Similary clinical features have been described in patients with a history of ___ therapy
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- most common form
- neck and shoulder regions - peripheral neuropathy, alcoholism, and hyperlipidemia - HIV-1 protease inhibitor |
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Asymmetric lipomatosis is __ disributed.
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randomly
- no associated with a clinical syndrome |
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Pelvic lipomatosis develops around the __ and __
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rectum and bladder
- associated symptoms (obstruction and uremia) - characteristic radiology |
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mediastinoabdominal lipomatosis and ___ lipomatosis are both associated with ___
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alcoholism
hyperlipidemia type II diabetes |
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The adipose tissue in lipomatosis is __
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- mature
- poorly circumscribed - +/- focal fibrosis |
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Lipoblastoma is preominantly a tumor of __ (age group) that affects mostly __
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- infancy (<3 yo)
- males - some cases seen up to 7-8 yo |
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lipoblastomas present as __, __, ___-growing mass in a __
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superficial, circumscribed, slow-growing, mass in a limb of a boy < 3 yo
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lipoblastomas that present as deep-seated, larger, infiltrative lesions are termed __
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lipoblastomatosis (diffuse form)
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Lipoblastomas __ recur
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typcially do NOT recur, if they do, it is usually with an infiltrative tumor (lipoblastomatosis)
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Lipoblastomas histologically are characterized by __
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- lobular architecture
- lobules composed of mature and immature adipocytes in VARYING degress of maturation - lobules separated by fibrous septae - IMMATURE LOBULES: consists of myxoid stroma with primitive mesenchymal cells, lipoblasts, and small capillaries (resembling myxoid liposarcoma BUT without atypia) - MATURE LOBULES: resemble lipoma but with some variation in cell size and more prominent nuclei - commonly may see foci of hibernoma-like cells and foci of extramedullary hematopoiesis |
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Key features allowing differentiation of the immature lobules of a lipoblastoma from myxoid liposaroma are __
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- lobular architecture
- lack of nuclear atypia - greaters spectrum of maturation |
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If a lipoblastoma recurs, it often shows ___ toward a __
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- maturation
- simple lipoma |
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Lipoblastoma show consistent chromosomal abnormalities involving __
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8q11-13 PLAG1 gene
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Myxoid liposaromas are __ in children <__ years old; however those occuring in the ___ age group tend to be __ grade tumors
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- exceedling rare
- 10 yo - myxoid liposarcomas occuring in the 10-20 yo age group tend to be very low grade tumors!! |
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Angiolipomas, unlike typical lipomas, are often __
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- mulitple (>50% cases)
- 50% painful or tender |
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Angiolipomas most often occur __
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- in males-
- early adulthood - wide anatomic distribution, but most often upper limb (forearm) and trunk |
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Most angiolipomas are <__cm
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<2cm (small)
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Angiolipomas __ recur, but __
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- do NOT recur
- BUT new lesions may continue to develop |
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A key diagnostic feature of angiolipomas
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- small fibrin thrombi
- their absence argues STRONGLY agianst the diagnosis |
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Angiolipomas with 90% or more vascularity are termed __
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cellular angiolipomas
- can have a spindled endothelial cell appearance - prominent pericapillary pericytes - resemble KS or primitive capillary hemangioma |
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Angiolipomas can be distinguished from Kaposi sarcoma and primitive capillary hemangioma by __
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- presence of intralesional mature adipocytes
- presence of microthrombi |
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Longstanding angiolipomas can show degenerative features
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- perivascular fibrosis and hyalinization
- stromal myxoid change |
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Angiolipomas consistently have a __ karyotype
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normal (unlike other fatty tumors)
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myolipoma is __. They usually occur in __ or __, and present as __
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- rare
- abdomen or pelvis - large tumors - slightly more common in females |
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DDX of a myolipoma (leiomyolipoma) includes ___ and ___
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1. angiomyolipoma
2. WD liposaroma with heterologous smooth muscle component |
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In a chondroid lipoma, the cytoplasm is finely ___, containing small __ droplets or ___-positive ___. Alternatively, the cytoplasm may be __
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- vacuolated
- lipid - PAS+ glycogen - eosinophilic and granular |
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Chondroid lipomas are highly ____tumors and common have foci of ___ and ___
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- vasular
- hemorrhage and fibrosis |
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IHC in a chondroid lipoma
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- lipoblast are WEAKLY S-100+ (increaseing + as they mature)
- vimentin+ - EMA- - Ki-67 <1% |
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Spindle cell lipomas are __ in the lower extremity
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distinctly RARE!!
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spindle cell/pleomorphic lipoma usually occur in __
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- older men (>55 yo)
- 90% are men (only 10% women) |
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spindle cell lipoma histologically consists of ___
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- bland mitotically inactive spindle cells in parallel short fascicles between fat cells
- spindle cells are short, undifferentiated cells with poorly defined cytoplasm - thick, ropey collagen bundles - many mast cells - +/- lymphs and plasma cells +/- myxoid stroma |
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pleomorphic lipoma histologically consists of __
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- similar to spindle cell lipoma PLUS:
- small spindled and round hyperchromatic cells - multinucleated giant cells with radially arranged nuclei (floret cells) |
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IHC in spindle cell/pleomorphic lipomas
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-spindle cells are CD34+ and RARELY S-100+
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A few spindle cell/pleomorphic lipomas are entirely intradermal and are more common in __
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women
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A lesion that looks like a spindle cell/pleomorphic lipoma, but occuring in deep tissue is better diagnosed as a ___
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atypical lipomatous tumor
- often supported by cytogenetics - also any lesion in an unusal site should be suspect |
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The spindle cell predominant spindle cell lipoma may show ___ , reminiscent of a schwannoma
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- nuclear palisading
Distnguished from a schwannoma by : - intralesion adipocytes - spindle cells are S-100- |
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Floret cells in pleomorphic lipomas exhibit a __ of nuclei and __ cytplasm
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- ring of nuclei
- eosinophilic cytoplasm |
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spindle cell/pleomorphic lipomas may contain __
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lipoblasts
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Distinction between a pleomorphic lipoma and a WD liposarcoma rest mainly on:
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- location (anatomic site and superifical nature)
- lack of marked variation in adipocyte size - minimal atypia in the adipocyte nuclei - spindle cell lipomas - abnormalities of 13q and 16q - WD liposarcoma - giant marker and ring chromosome (12q) |
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hibernoma is a __ neoplasm consisting of at least in part __
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- rare
- brown fat cells with granular, multivacuolated cytpolasm admixed with variable amounts of white fat |
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Residual brown fat (not hibernoma) is common found in the __ and __
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cerivcal and axiallary regions around lymph nodes
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Hibernomas usually present in __
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- yound adults
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Most common site for a hibernoma
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- thigh
- followed by trunk, upper extr, H&N - <10% occur intrabdominally or intrathoracically |
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Spindle cell and myxoid variants of hibernoma tend to occur in the ___
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posterior neck/shoulder region similar to spindle cell/pleomorphic lipomas
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There are six variants of hibernoma based on __
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- stromal background
1. granular or eosinophilic 2. mixed variant with pale and esoinophiic cells 3. lipoma-like variant (small foci of white fat and multivacuolated lipoblast-like cells) 4. myxoid variant 5. spindle cell variant (thick collagen bundles, scattered mast cells, mature adipose) 6. pale variant (pure pale cells) |
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Hibernoma cells have a __ placed nucleus
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centrally
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In the spindle cell variant of hibernoma, the spindle cells are CD__+
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CD34+ (similar to those of spindle cell lipomas)
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IHC in hibernomas
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- S-100+
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Hibernomas are grossly well-___ and ___. Average size is ___. Majority are located in the ___, with __% being ___, most often in the __
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- well-circumscribed and encapsulated
- 5-10 cm - subcutaneous tissues - 10% being intramuscular, most often in the thigh |
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DDx of hibernoma: remember that a myxoid liposarcoma may contain __
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hibernoma-like cells
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Atypical lipomatous tumor (ALT)/WD liposarcoma are considered ___ (behavior)
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intermediate (locally aggressive) malignant mesenchymal neoplasms
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ALT/WD lipsarcoma show at least in part significant ___ and at least focal ___
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- variation in cell size
- nuclear atypia in BOTH the adipocytic and stromal cells |
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How often do ALT/WD liposarcoma metastasis?
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- they do not show metastatic potential UNLESS they dedifferentiate
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ALT/WD liopsarcoma account for __% of liposarcomas
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40-45%!! Most common type!
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ALT/WD lipsarcoma most often present in ___
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- middle aged adults (peak in 50's)
- M=F (except for spermatic cord lesions! ;) ) |
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ALT/WD liopsarcoma: most common sites
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- usually deep-seated in limbs (especially thigh)
- retroperitoneum - paratesticular - mediastinum - subcutaneous tissues - RARELY in the skin |
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Grossly, ALT/WD liposarcoma__
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- usually well-circumscribed, lobulated
- IN RETROPERITONEUM may be multiple discontinuous masses - rarely infiltrative pattern |
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4 main subtypes of ALT/WD liposarcoma
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1. adipocytic (lipoma-like) MOST COMMON
2. sclerosing SECOND MOST COMMON (most often retroperitoneal or paratesticular) 3. spindle cell 4. inflammatory (RARE, retroperitoneum) Mixed type is common, especially in retroperitoneum |
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DDX of inflammatory WD liposarcoma
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1. inflammatory myofibroblastic tumor
2. Hodgkin lymphoma 3. Castleman disease 4. NHL presence of an adipocytic component (which may be scarce) or the presence of bizarre multinucleate stromal cells is a clue |
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Heterologous differentiation in a WD liposarcoma?
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Yes! although rare!
- smooth or skeletal muscle differentiation - metaplastic bone formation MUST distinguish heterologous differentiation in a WD liposarcoma from that arising in a dedifferentiated liposarcoma HMB45- (if AML in DDX) |
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cytogenetic abnormality of ALT/WD liposarcoma
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- supernumerary circular (ring) and giant rod chromosomes
-- contain amplification of 12q region incluidng MDM2 gene |
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Risk of dedifferentiation of ALT/WDLPS is based larged on __
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site and lesional duration
- probably >20% for retroperitoneal - <2% in limbs |
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Dedifferentiated liposarc show __, either in the primary or recurrent tumor, from ___ to ___
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- transition
- ALT/WDLPS to NON-LIPOGENIC sarcoma of variable histologic grade |
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Most (about __%) of dedifferentiated liposarc arise __, while __% occur in __
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- 90%
- de novo - 10% occur in recurrences |
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Occurence of dedifferentiated liposarc is most common in the __ and rare in the __
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- most common in retroperitoneum, spermatic cord
- rare in subcutaneous tissues |
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Clue to dediff in a limb lesion is __
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history of recent increase in size of a long standing mass
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Histologic hallmark of dediff liposarc
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- seeing the transition from ALT/WDLPS to any type of non-lipogenic sarcoma (most often high grade)
- the areas of dediff are most often recognizable grossly!!! |
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Significance of microscopic foci of dedifferentiation in a liposarocoma
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- uncertain!!
- usually the areas of dedifferentiation are grossly recognizable - note: dediff can be more gradual and low grade (uncommon) |
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Most common histologic appearance of dediff liposarc
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- unclassifiable MFH-like pleomorphic sarcoma
- intermediate to high grade myxofibrosarcoma |
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Dediff liposarc appears to be clinically __ aggressive compared to other high grade pleomorphic sarcomas
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less aggressive
- careful sampling, looking for the WD liposarc component is important |
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The local recurrence of a dediff liposarcoma may be entirely __
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well differentiated
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Dediff liposarcoma cytogenetic findings
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- similar to ALT/WDLPS, ring or giant marker chromosomes
- still limited number of cases examined to determine if a consistent difference between the two exists |
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Dediff liposarc: tendency to recur locally is __% and distant metastases in ___%
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- 40% recur locally; almost all retroperitoneal tumors recur if followed 10-20 years
- 15-20% distant metastasis - overall mortality about 30% over 5 years |
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How useful is the extent of dedifferentiated areas at predicting the outcome?
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It is NOT!
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5% of dediff liposarcomas can show foci of __ differentiation
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- heterologous
- most commonly myogenic (smooth muscle or rhabdomyosarcomatous) |
