Nevoid melanoma.

Nevoid melanoma is a rare subtype of melanoma that is regarded as one of the most difficult to diagnose. It clinically and histopathologically resembles a benign nevus, often resulting in misdiagnosis and allowing the skin cancer to progress further before it is identified. It presents clinically as an elevated brown papillomatous polypoid lesion on the trunk, arms, or legs; microscopically, it is defined by its relative symmetry, deep mitoses, and nevus-like melanocytes. In recent decades, studies have been carried out to understand nevoid melanoma and how it develops, progresses, and can be better identified. Technologic advancements in dermatoscopy, microscopy, and immunohistochemistry have allowed dermatologists and pathologists to have a better understanding of this variant of melanoma to permit an earlier diagnosis. Although nevoid melanoma is not any less aggressive or harmful than other subtypes of melanoma, delayed diagnosis of this skin cancer can be associated with adverse patient outcomes.