Skin - Melanocytic tumor
Melanoma
Desmoplastic melanoma

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

Revised: 21 February 2017, last major update May 2013

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

PubMed Search: Desmoplastic melanoma

Cite this page: Desmoplastic melanoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumormelanocyticdesmoplasticmelanoma.html. Accessed March 24th, 2017.
Definition / General
  • Rare variant of spindle cell melanoma seen in older adults in sun exposed skin
  • A type of nodular (vertical growth) melanoma with scanty spindle cells, prominent desmoplastic stroma and often minimal atypia
  • First described in 1971 (Cancer 1971;28:914)
Terminology
  • Also called desmoplastic neurotropic melanoma if neuroma-type features with prominent nerve involvement (Adv Anat Pathol 2005;12:92)
Epidemiology
Sites
  • 72% in head, neck
Clinical Features
  • Often nonpigmented and mistaken for nonmelanocytic lesion, such as scar
  • Usually advanced thickness at presentation (Br J Dermatol 2005;152:673)
Case Reports
Treatment
Clinical Images

Images hosted on other servers:

2.5 cm scalp lesion

Dermoscopy
  • Features of regression (white scar-like areas, peppering); also multiple colors, linear irregular vessels or milky red areas (Br J Dermatol 2008;159:360)
Micro Description
  • Poorly circumscribed; focal fascicular pattern of scanty spindle cells with prominent desmoplastic stroma
  • Tumor cells may have minimal atypia
  • Solar elastosis (82%), amelanotic (71%), deep invasion, perineural infiltration (35%), lymphoid aggregates at periphery (37%); may grow in peripheral nerve sheath pattern
  • May be pure or combined with classic melanoma (pure have better prognosis, Am J Surg Pathol 2004;28:1518)
  • 15% have no evidence of intraepidermal melanocytic component
Micro Images

Images hosted on other servers:

Desmoplastic vs. non-desmoplastic melanoma

Hypocellular spindle cells (fig. 1)

Mixed with classic melanom (fig. 2)

Atypical spindled cells (fig. 1)

81 year old man with scalp lesion


Various images

S100 and T311 (tyrosinase) staining


HMB45 and Mart1 negative

MITF positive

Cytology Description
  • Clean background; aggregates of pleomorphic spindle cells mixed with fibrous stroma and single cells
  • Fine, wispy and delicate cytoplasm at nuclear poles, nuclei are elongated and plump with irregular contours, deep grooves and folds and dark coarse chromatin with variably prominent nucleoli (Cytojournal 2007;4:18)
  • Compared to other melanomas, is less cellular and less often has intranuclear cytoplasmic inclusions and mitotic figures (Am J Clin Pathol 2008;130:715)
Cytology Images

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Various images

Positive Stains
Negative Stains
Molecular / Cytogenetics Description