Skin - Melanocytic tumor
Melanoma
Superficial spreading melanoma

Author: Christopher Hale, M.D. (see Authors page)

Revised: 20 February 2017, last major update May 2013

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Superficial spreading melanoma

Cite this page: Superficial spreading melanoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumormelanocyticsuperficialspreading.html. Accessed October 23rd, 2017.
Definition / general
  • Traditional considered most common type of melanoma (50 - 75%) but lentigo maligna may actually be more common in patients with extensive sun exposure (J Am Acad Dermatol 2008;58:1013)
  • Recently diagnosed tumors are thinner with less ulceration than in the past (Cancer 2008;113:3341)

Risk factors:
  • Extensive sun exposure during childhood, family history of melanoma, large numbers of benign nevi and dysplastic nevi
  • Recommended to evaluate vertical growth phase as prognostic factor for thin (< 0.76 mm) tumors (Am J Surg Pathol 2003;27:717)
Epidemiology
  • Usually affects light skinned individuals, young adults to elderly
Sites
  • Often trunk and extremities
Clinical features
  • 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
Case reports
Dermoscopy
  • Multicomponent pattern, asymmetry and multiple colors
  • Also atypical reticular pattern (irregular holes and thick lines) with a sharp demarcation, bluish white veil, irregular linear vessels, central ulceration and irregularly distributed dots
Clinical images

Images hosted on other servers:

Various images

Reticular pattern

Homogeneous area

Irregular black tumor with periumbilical elevation

Microscopic (histologic) description
  • 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 and pigmented parakeratosis
  • Invasive component generally of epithelioid subtype
  • Variant is composed predominantly of large nests (Mod Pathol 2012;25:838)
Microscopic (histologic) images

Images hosted on other servers:

Superficial spreading melanoma and satellite nodule

Beta catenin expression in primary

S100A6 staining (negative)

Positive stains
Molecular / cytogenetics description