Unusual variants of malignant melanoma.

Melanoma is as diverse in its presentation as it can be in its behavior. This contribution will review the clinical and histologic features of some of the more unusual variants of malignant melanoma that clinicians and pathologists are likely to encounter. There will be a disproportionate focus on the histopathology and prognosis because the clinical presentation of these lesions is in most cases, elusive, and in some cases, frankly deceptive. The discussion will include desmoplastic melanoma, nevoid melanoma, spitzoid melanoma, angiotropic melanoma, and malignant blue nevus.