Polypoid melanoma: a virulent variant of nodular melanoma. Report of three cases and literature review.

We report the cases of three patients with polypoid melanoma. In no case was there microscopic evidence of melanoma cell invasion below the papillary dermis. In the polypoid variant of nodular melanoma, melanoma cells accumulate in large volume above the skin's surface. This increase in tumor volume encourages dislodgment of melanoma cells that are carried to superficial lymphatic vessels without invading the reticular dermis; this feature differentiates polypoid melanoma from the nonpolypoid nodular variant. Although polypoid melanoma is considered the most malignant form of melanoma, our findings, albeit limited to three cases, suggest that early diagnosis and prompt surgical excision may provide a favorable 5-year survival rate.