Last major update: November 2008 - next update November 2009
Revised: 22 September 2009
Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.
Copyright: (c) 2002-2009, PathologyOutlines.com, Inc.
● Traditionally considered the most common type of melanoma (50-75%), but lentigo maligna may be more common in patients with extensive sun exposure ()
● Recently diagnosed tumors are thinner with less ulceration than in the past (Cancer 2008 Nov 5 [Epub ahead of print])
● Usually affects light skinned individuals, young adults to elderly, often trunk and extremities
● 77 year old man with tumor in vertical growth phase with microscopic satellite nodule (Archives 2003;127:e365)
● Extensive sun exposure during childhood, family history of melanoma, large numbers of benign nevi, dysplastic nevi
● Recommended to evaluate vertical growth phase as prognostic factor for thin (< 0.76 mm) tumors (AJSP 2003;27:717)
● Variegated, black, brown, tan, blue, pink or white
● Slightly elevated, flat and irregular margins, often with an indentation or notch
● May have white areas of tumor regression or nodular areas of deep dermal invasion
Irregular black tumor with Various images
elevation in periumbilical area
● Multi-component pattern, asymmetry and multiple colors
● Also atypical reticular pattern (irregular holes and thick lines) with a sharp demarcation, blue-white veil, irregular linear vessels, central ulceration, irregularly distributed dots
Various images Reticular pattern with dark Homogeneous area,
broadened network irregular dots and
globules and irregular
● Classified based on radial growth component (has nothing to do with level of dermal invasion)
● Noninvasive areas have asymmetry and poor circumscription, irregular acanthosis, irregular lentiginous and nested proliferation, uniform atypical melanocytes with nests and pagetoid cells
● Also transdermal migration, nuclear pleomorphism, dusty pigmentation, apoptosis of individual melanocytes, pigmented parakeratosis
● Invasive component generally of epithelioid subtype
Superficial spreading melanoma Clark level III
and satellite nodule
S100A6 staining (negative) Beta catenin expression in primary
but not metastasis
Molecular / cytogenetics
● Exon 15 BRAF mutations in 29% (J Invest Dermatol 2005;125:575)
End of Skin-Melanocytic Tumors > Superficial spreading melanoma
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