Polypoid melanoma, a virulent variant of the nodular growth pattern.

Thirty-two patients who had polypoid melanoma were identified in a registry of 552 melanoma patients. The tumor is regarded as a variant of nodular melanoma and is associated with an increased thickness, more frequent ulceration than the nodular variant of melanoma, younger patient age, and higher probability of occult metastasis. Polypoid melanomas were most frequently present on the trunk, and were also encountered in unusual sites, such as the mucosa of the nose, hard palate, and anorectal junction. In terms of survival, the patients with the polypoid nodular variant fared significantly worse than those with nonpolypoid nodular (P = 0.05) and those with superficial spreading (P = 0.003) melanomas. The five-year survival rate for polypoid variant was 42%, in contrast to 57% for the nonpolypoid nodular and 77% for the superficial spreading melanomas. The poor prognosis of patients who have polypoid melanoma is most likely due to its being the type of melanoma with the deepest penetration at the time of surgical excision.