Melanoma Flashcards
Precursors of Melanoma
Dysplastic melanocytic nevi
Congenital melanocytic nevi
Dysplastic melanocytic nevus
onset: child and adult White AD 30-50% in non familial melanoma Trunk; extremities Diameter upto 15mm
Larger and more variegated in color, asym-
metricinoutline,andwithirregularborders;theyalsohavecharacteristichistologic eatures
(out of step)
“fried egg, targetoid”
DERMATOPATHOLOGY Hyperplasia and proli era- tiono melanocytesinasingle- le,“lentiginous” pattern in the basal cell layer either as spindle cells or as epithelioid cells, and as irregular and dyshesive nests. “Atypical” melanocytes, “bridg- ing” between rete ridges by melanocytic nests; spindle-shaped melanocytes oriented parallel to skin sur ace. Lamellar broplasia and concentric eosinophilic brosis (not a constant eature). Histologic atypia do not always correlate with clinical atypia. DN may arise in contiguity with a compound MN (rarely, a junctional nevus) that is centrally located.
Tx: Surgical excision of lesions with narrow margins
Lifetime Risks of Developing Primary Malignant Melanoma
General population: 1.2%.
■ Familial DN syndrome with two blood
relativeswithmelanoma:100%.
■ All other patients with DN: 18
Congenital melanocytic nevus
Birth equal all races developmental defect in neural crest- derived melanoblasts- Within 10 weeks to 6 months inutero Split nevus- (before 24 weeks)
PE / plaque with or without coarse ter- minal dark brown or black hairs
sharply demarcated
large lesions wormy or soft
Skin surface smooth or “peb- bly,”mamillated,rugose,cerebriorm,bulbous, tuberous, or lobular
HISTOPATHOLOGY Nevomelanocytes occur as well-ordered clusters (theques) in the epidermis and in the dermis as sheets, nests, or cords. A di use in ltration o strands o nevomelanocytes in the lower one-third o the reticular dermis and subcutis is, when present, quite speci c or CMN. In large and giant CMN, the nevomelanocytes may extend into the muscle, bone, dura mater, and cranium.
Tx: excision w full thickness graft
lifetime risk or development of melanoma in largeCMN
6.3%
Poor prognosis- detected late
50% prod melanoma at 3-5 yo.
Lifetime risk of developing Malignant melanoma (Small CMN)
1-5%
Cutaneous Melanoma. How many percent of newly diagnosed cancer in men and women
most malignant tumor of skin
5%- men
6% women
Major genes involved in melanoma and mutation.
Chrom 9p21
cyclin dependent kinase inhibitor 2A( CDKN 2A) -40%
Mutation in BRAF and MC1R - 60%
Melanoma skin type
1,2
Melanoma (RF )
■ n mb (>50) d iz (>5mm) m cicvi
Number of dysplastic nevi (>5)
T in staging does not apply to what type of melanoma
Nodular
Frequency of melanoma by type of tumor:
SSM, 70%; NM, 15%; LMM, 5%; and acralandunclassi edmelanoma,10%
Lentigo maligna when there is already invasion to the dermis is called:
LMM
LMM
inc. what skin types
Gray and blue areas rep what?
Med 65
equal
Face, neck, dorsa of forearms and hands
Skin type 123
LMMistheappearanceo variegatedred, white,andblueandalsoo papules,plaques, or nodules (Fig. 12-10B). T us, LMM is the sameasLMplus(1)grayareas(indicate ocal regression) and blue areas [indicating dermal pigment (melanocytes or melanin)] and (2) papules or nodules, which may be blue, black, or pink
DP: Melanocytes atypical, single layer in basal layer
TX: Very early: Imiquimod
excise 1cm beyond lesion
Sentinel node in >1mm thickness
Superficial Spreading Melanoma
What areas? Morphology. age. Gender. Skin type
Upper back.
Morph: elevated, at lesion (plaque). The pigment variegation o SSM
issimilarto,butmorestrikingthan,thevarietyo colorpresentinmostLMM.Thecolordisplayisa mixtureo brown,darkbrown,black,blue,andred,withslate-grayorgrayregionsinareaso tumor regression.
30-50 (med 37)
Females
Type 1,2
