Cutaneous desmoplastic melanoma: reappraisal of morphologic heterogeneity and prognostic factors

Am J Surg Pathol. 2004 Nov;28(11):1518-25. doi: 10.1097/01.pas.0000141391.91677.a4.


Desmoplastic melanoma (DM) is a variant of melanoma, which may be confused with nonmelanocytic benign or malignant spindle cell proliferations. The histologic hallmark of DM is the presence of fusiform melanocytes dispersed in a prominent collagenous stroma. Phenotypic heterogeneity of DM is underrecognized. Desmoplasia may be prominent throughout the entire tumor ("pure" DM) or represent a portion of an otherwise nondesmoplastic melanoma ("combined" DM). We reviewed melanomas with desmoplasia from 92 patients seen at a single institution between 1980 and 2002. Fifty-five of the tumors were pure DM. Thirty-seven were classified as combined. Mean follow-up of patients was 46 months for those alive at the last follow-up. Univariate analysis of clinical and pathologic parameters revealed four significant variables for disease-free survival: Clark level (IV vs. V; P = 0.005), DM subtype (pure vs. combined; P = 0.01), tumor mitotic rate (<1, 1-4, >4 mitoses/mm; P = 0.01), and tumor thickness (<1 mm, 1-4 mm, >4 mm; P = 0.02). Only histologic subtype (P = 0.02) and Clark level (P = 0.05) were independently significant by Cox regression analysis. Our results indicate that distinguishing pure from combined forms of DM is clinically relevant for prognosis (pure forms being associated with longer disease-specific survival). Failure to make this distinction may account for conflicting reports in the literature on the biologic behavior and prognosis of DM.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Female
  • Fibrosis / pathology
  • Humans
  • Male
  • Melanoma / mortality
  • Melanoma / pathology*
  • Middle Aged
  • Prognosis
  • Retrospective Studies
  • Skin Neoplasms / mortality
  • Skin Neoplasms / pathology*
  • Survival Analysis