1 Gp - Pathology 1 - Pigmented Lesion

Front 1

Checklist for Pigmented Lesion

Back 1

Assymetry
Border irregularity
Color variation
Diameter (>6-7mm)
Elevation or nodularity

NB: Itching and bleeding are lesser signs

Front 2

Compound Naevus

Back 2

A pigmented, uniform-colored, elevated lesion with well-defined border

Naevu cells (benign melanocytes) are found in both:
i) the epidermal-dermal junction; and
ii) deep in the dermis.

Front 3

Intradermal Naevus

Back 3

An elevated, pigmented/flesh-colored lesion with well-defined border. e.g. preauricular naevus

Naevus cells (Benign melanocytes) have migrated and occupy the dermal layer
-there are NO nests of naevus cells in the epidermal-dermal junction

Front 4

Junctional Naevus

Back 4

A flat pigmented lesion of homogeneous color

Naevus cells (benign melanocytes) form nests at the epidermal-dermal junction

Front 5

Malignant Melanoma

Back 5

A large (>1cm) asymmetrical lesion with flat and elevated area, variable color and irregulr border.

i) Cytological features of malignancy
-cellular pleomorphism, numerous mitoses
-large irreg. nuclei, prominent red nucleoli
ii) Radial and Vertical growth
iii) Attenuation of the epidermis above the nodule
iv) Lymphocytic reaction beneath the melanoma
v) Heavy pigmentation

NB: the symmetry, well-defined border exclude melanoma

Front 6

Radial growth phase of melanoma

Back 6

Nests of malignant melanoma grows in the epidermis, non-invasive

Front 7

Vertical growth phase of melanoma

Back 7

Invasive malignant melanoma
-invades the basement membrane, forms large mass in dermis and metastasize

Front 8

Breslow's depth

Back 8

-an old system of a major prognostic factor of melanoma
--e.g. 5yr survival of melanoma:
i) 0.76mm=97% vs 8.0mm=32%
-now replaced by AJCC depth
-measures the depth of tumor cell invasion:
---epidermal granular layer to the deepest point of invasion
-most accurately measured by evaluating the whole tumor via excisional biopsy
---cf. wedge or punch biopsy are inaccurate (underestimation)

Front 9

Nodular Melanoma

Back 9

Unlike superficial spreading melanoma which initially grows in the epidermis and subsequently invades the dermis then give rise to elevation,
nodular melanoma is elevated from the start.

This form of melanoma is frequently misdiagnosed, so tumor has time to deeply penetrate the dermis to give early metastases.

Front 10

Dysplastic naevus

Back 10

aka atypical mole

Atypical because:
i) it's larger
ii) nuclear atypia
iii) some dysplastic naevi can turn into melanoma
--cf. common naevi v. rarely shows these changes

Many has fried-egg appearance:
-a symmetrical elevated center which is uniform in color
-surrounded by a pigmented rim, which has a well-defined border and uniform color

NB: the symmetry, well-defined border exclude melanoma

Front 11

Spread of melanoma

Back 11

1) to regional nodes
--corresponding area should be checked in any suspected pigmented lesions
2) then hematogenous:
-commonly liver, lung & brain
-but can spread virtually anywhere

NB:
-brain has no lymphatics hence brain metastases must be hematogenous
-melanoma metastases can range from black to white!!

Front 12

Clark method of measurement

Back 12

old system, inaccurate.

Level I: melanoma in situ (mis)
-melanoma confined to epidermis

Level II:
-Melanoma invades into the dermis

Level III-IV:
-Melanomas invade deeper thru the dermis
-BUT still contained completely within the skin

Level V:
-Melanoma penetrate into subcutis (3rd layer of skin) - the skin fat beneath the dermis