Acral Amelanotic Melanoma With a Sporotrichoid Pattern and Associated Vitiligo in an Elderly Patient: A Case Report.

Acral amelanotic melanoma (AM) is a rare and aggressive melanoma subtype that frequently presents with a diagnostic delay due to its atypical characteristics. Sporotrichoid spread, suggesting lymphatic dissemination, is rarely seen. Vitiligo, although usually benign, may signal underlying malignancy when appearing de novo in older adults. An 82-year-old woman presented with an 18-month history of a foul-smelling, ulcerated nodular lesion on the left foot, accompanied by multiple erythematous nodules in a linear pattern ascending to the ipsilateral groin. She also had achromic macules consistent with non-segmental vitiligo, present for two years. A biopsy revealed invasive nodular AM (Breslow ≥4 mm, Clark level IV) with perineural and vascular invasion. She was referred for oncologic evaluation and treatment. This case highlights a rare clinical presentation of acral AM with sporotrichoid spread and associated vitiligo in an elderly patient. Given its frequent misdiagnosis, clinicians should consider AM in atypical, nonresponsive lesions, particularly when associated with late-onset vitiligo.