Primary Dermal Melanoma: A Distinct Subtype of Melanoma | Dermatology | JAMA Dermatology | JAMA Network
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January 2004

Primary Dermal Melanoma: A Distinct Subtype of Melanoma

Author Affiliations

From the Dermatology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, Calif (Dr Swetter); and the Departments of Dermatology (Drs Swetter and Harvell and Mr Ecker), Surgery (Dr Johnson), and Pathology (Dr Harvell), Stanford University Medical Center, Stanford, Calif. Dr Harvell is currently with North Georgia Dermatopathology, Marietta, Ga. The authors have no relevant financial interest in this article.

Arch Dermatol. 2004;140(1):99-103. doi:10.1001/archderm.140.1.99

Background  The term primary dermal melanoma has been used to describe a subtype of melanoma confined to the dermis and/or subcutaneous fat that histologically simulates metastasis but is associated with an unexpectedly prolonged survival. We report 7 cases of primary dermal melanoma diagnosed from 1998 to 2002 with no identifiable junctional or epidermal component or nevoid precursor. Histopathologic and immunohistochemical features were compared with known cases of cutaneous metastasis and nodular melanoma in an attempt to differentiate this entity from clinical and pathologic mimics.

Observations  Seven patients had a single dermal and/or subcutaneous focus of melanoma. Metastatic staging workup findings were negative, including results fromsentinel node and imaging studies. Mean Breslow depth was 7.0 mm, and mean maximum tumor diameter was 6.2 mm. The study cohort showed 100% survival at mean follow-up of 41 months (range, 10-64 months). Immunohistochemical analysis with S100, HMB-45, Ki-67, CD34, and p75 antibodies showed no significant staining patterns compared with metastatic and nodular melanomas.

Conclusions  Primary dermal melanoma appears to be a distinct subtype of melanoma based on the excellent prognosis associated with this case series and others. Additional research focusing on cause, appropriate staging, and outcome of previously identified solitary dermal metastasis is warranted to further delineate this entity.