Benign Skin Lesions (Full)

Front 1

Ephelids

Back 1

• “Freckles”
• Lighten in Winter and darken in Summer.
• Increased pigment at basal layer.

Front 2

Melasma

Back 2

• “Mask of pregnancy”
• Diffuse patchy pigment on face.
• Pigment in epidermis and/or dermis.

Front 3

Vitiligo

Back 3

• White patches
• Complete loss of pigment.
• Loss of melanocytes and pigment.

Front 4

Albinism

Back 4

• Absence of pigment in skin, hair, and nails.
• Autosomal recessive
• Loss of pigment with normal appearing
melanocytes.

Front 5

Mongolian Spot

Back 5

• Bluish-gray lumbosacral patch in newborns.
• More common in pigmented races.
• Resolves in early childhood.
• Sparse deep dendritic melanocytes.

Front 6

Café au lait

Back 6

• Light brown patches.
• 6 or more 0.5 cm in child  Neurofibromatosis.
• 6 or more 1.5 cm in adolescence 
Neurofibromatosis.
• Increased pigment in basal layer.

Front 7

Lentigo

Back 7

• Macular pigmented lesions on
sun exposed skin
• Indication of photodamage
• Increased melanocytes at
Dermal-Epidermal (DE) junction
without nest formation.

Hint 7

Front 8

Junctional Nevus

Back 8

• Macular pigmented lesion
• Nests of melanocytes along the
DE junction

Hint 8

Front 9

Compound Nevus

Back 9

• Slightly raised pigmented
plaque
• Nests of melanocytes at DE
junction and within the dermis

Hint 9

Front 10

Intradermal Nevus

Back 10

• Papular lesions
• Light or dark
• Nests of melanocytes within
the dermis

Hint 10

Front 11

Spitz's Nevus

Back 11

• Papular lesions of children
• Historically “benign juvenile
melanoma” – avoid this term!
• Epithelioid and spindle cell
melanocytes can look atypical
• Nests often vertically oriented

Hint 11

Front 12

Blue Nevus

Back 12

• Bluish papule or macule
• Deeper melanin appears blue
due to Rayleigh scattering
• Heavily melanized dendritic
melanocytes within the mid to
deep dermis

Hint 12

Front 13

Halo Nevus

Back 13

• Depigmented zone around a nevus
• Common in children – worrisome in
elderly
• Lymphocytes surround benign
nests of melanocytes

Hint 13

Front 14

Congenital Nevus

Back 14

• Large “bathing trunk nevus”
has increased risk of melanoma
• Small form not strongly
associated with melanoma
• Benign melanocytes extend more
deeply into dermis and even
subcutaneous tissues.

Hint 14

Front 15

Dysplastic Nevus

Back 15

• Larger irregular morphology
• Heritable Melanoma Syndrome
• Controversial Diagnosis
• Atypical melanocytes
• Nests stream horizontally
• Severely atypical treated as
melanoma in situ

Hint 15

Front 16

Nevus

Back 16

• Slight irregularity of border and color
• Dermoscopy reveals a fine reticular
pigment network without atypical
features.

Front 17

Actinic Keratosis

Back 17

• Scaly/hyperkeratotic lesions on
sun exposed skin.
• Considered pre-cancerous, but
only about 1% evolve to SCC
• Atypical keratinocytes in lower
epidermis
• Underlying solar elastosis
(bluish dermis)
• Overlying parakeratosis
(retained nuclei)

Hint 17

Front 18

Seborrheic Keratosis

Back 18

• Appear as one gets older – most
common in elderly.
• “Stuck on” lesions – keratotic with
varying shades of brown, but can be
skin colored or even erythematous.
• Can have rough or smooth surface
and be large or small.
• May have keratotic pores or
pseudocysts.
• Sometimes inflamed or bleeding from
picking.
• Not limited to sun exposed surfaces.

Hint 18

Front 19

Acanthosis Nigricans

Back 19

• Most common in obesity but rarely
associated with internal tumors.
• Clinically velvety brown plaques –
usually in the axillae

Front 20

Fibroepithelial Polyps

Back 20

• AKA Acrochordons.
• Commonly known as skin tags.
• More common in obesity involving
neck, axillae, and groin areas.
• Can be associated with Acanthosis
Nigricans.

Front 21

Epidermoid Cysts

Back 21

• Sometimes referred to as “sebaceous
cysts”, but they aren’t.
• Expansion of hair follicle forms epithelial
lining. Also form as EIC’s from trauma.
• Pilar cyst has trichilemmal keratinization.
• Acne cyst results from follicular rupture.

Hint 21

Front 22

Sebaceous Hyperplasia

Back 22

• Very common in middle aged and
elderly men.
• Umbilicated pale yellowish papules.
• Benign tumor of sebaceous glands.

Front 23

Syringoma

Back 23

• Seen under the eyes of women.
• Small skin colored papules.
• Benign tumor of eccrine sweat glands.

Front 24

Nevus Sebaceous

Back 24

• Birthmark lacking hair when on scalp.
• Prepubertal may appear smooth yellow/orange.
• Adolescent has cobblestone surface.
• Adult form is prone to basal cell carcinoma.

Front 25

Adenoma Sebaceum

Back 25

• Central facial papules.
• One manifestation of Tuberous
Sclerosis.
• Angiofibromas, histologically.

Front 26

Neurofibroma

Back 26

• Neurofibromatosis / Von Recklinghausen’s.
• Solitary lesion more commonly.
• Spindle cell tumor of Schwann cells and fibroblasts.

Front 27

Xanthelasma

Back 27

• Yellowish plaques on eyelids.
• Not strongly associated with increased
lipids – other xanthomas associated with
increased lipids.
• Foamy histiocytes contain the lipid.

Front 28

Diseases associated with Trichilemmoma

Back 28

Cowden Syndrome/ Breast carcinoma

Front 29

Diseases associated with Sebaceous Adenoma

Back 29

Muir-Torre Syndrome/Mult CA

Front 30

Diseases associated with Angiofibromas

Back 30

Tuberous Sclerosis

Front 31

Diseases associated with Neurofibromas

Back 31

When multiple - Von Recklinghausen's

Front 32

Diseases associated with Xanthomas

Back 32

When multiple, associated with lipid disorders

Front 33

Dermatofibroma

Back 33

• Common on the legs of women.
• Brownish papule with “dimple sign”.
• Benign fibrohistiocytic tumor.

Front 34

Keratoacanthoma

Back 34

• Rapidly growing “volcanoe-like” lesion with
keratin center.
• Can resolve spontaneously.
• Rare metastasis has prompted many to
consider this a form of Squamous Cell
Carcinoma which it resembles histologically.

Front 35

Angiomas

Back 35

• Cherry angiomas most common
• Strawberry angiomas in children often
resolve spontaneously
• Pyogenic granuloma is a traumatic variant.
• Port wine stains are very common in the
form of a “stork bite” on posterior neck.
• Venous Lakes occur on lips and ears.
• Telangiectasia of face is more commonly due
to sun damage than rosacea.

Front 36

Keloid

Back 36

• Hypertrophic scars that extend beyond
initial injury.
• More common in African-Americans

Front 37

Lipoma

Back 37

• Soft mobile subcutaneous mass.
• Solitary or multiple.
• Stable size.
• When tender = angiolipoma.

Front 38

Verruca

Back 38

Warts

• Verruca vulgaris – common wart
(seeds = microhemorrhage).
• Plantar warts – common warts
“pounded inward”.
• Verruca plana – flat warts.
• Condyloma accuminatum – genital,
STD, HPV 6,11 most common.
• Molluscum Contagiosum – pox virus,
not HPV – children and STD in adults.
• Mosaic warts – extensive plantar
involvement.