Polypoid Melanoma: A Rare and Aggressive Variant

A 57-year-old man presented with a several-month history of a bleeding, lobulated mass on the left lower back and a palpable left axillary lymph node. Excisional biopsy revealed an 11-mm-thick, lobulated, sessile polypoid nodular melanoma (pT4b) with Clark level IV invasion, a mitotic rate of 4/mm², and associated ulceration. A sentinel lymph node biopsy was not performed, as the patient was subsequently lost to follow-up. Immunohistochemistry was positive for SOX10, MART-1, and HMB-45, confirming melanocytic differentiation. The lesion was initially excised with 2-cm clinical margins, and histopathologic evaluation confirmed negative margins. Although referral was made for wide local excision and sentinel lymph node biopsy for definitive staging and management, the patient did not return for additional surgical intervention and was lost to follow-up. Polypoid melanoma (PM) typically presents as rapidly enlarging, exophytic, and often ulcerated or bleeding nodules that can mimic benign vascular or inflammatory lesions (e.g., pyogenic granuloma), which may delay diagnosis. Prompt recognition and early biopsy of atypical exophytic nodules are therefore essential. Management emphasizes timely wide excision and accurate pathologic staging, with multidisciplinary coordination and consideration of adjuvant systemic therapy (such as immune checkpoint inhibitors or targeted agents) when indicated by stage. This case highlights the need to maintain a high index of suspicion for PM in atypical, rapidly growing, or bleeding cutaneous nodules.