Amelanotic melanomas presenting as red skin lesions: a diagnostic challenge with potentially lethal consequences

To characterize epidemiologic and clinical features of red primary amelanotic melanomas, an atypical presentation of melanoma that is underemphasized in patient and physician education.

Review of a prospectively collected melanoma database identified 46 patients with red amelanotic melanomas, whose clinical features were compared with 329 patients with pigmented melanomas from the same database and same timeframe from January 1964 to September 2005.

Red amelanotic melanomas represented 3.9% of all melanomas recorded in our database and accounted for nearly 70% of amelanotic melanomas. Melanoma was included in the clinical differential diagnosis in 32% of red amelanotic melanomas vs. 94% of pigmented melanomas (P<0.001). Red amelanotic melanomas more commonly underwent shave biopsy (55 vs. 12%, P<0.001) and more likely had positive deep margins (35 vs. 9%, P<0.001) but had comparable risks of metastasis and mortality.

Red amelanotic melanomas are often misdiagnosed clinically but carry a mortality risk comparable to pigmented melanomas. Clinicians screening for melanoma should be more vigilant in considering melanoma in the differential diagnosis of red skin lesions.