Amelanotic Malignant Melanoma: A Case Report

Amelanotic malignant melanoma (AMM) is a skin cancer that arises from mutated melanocytes that lack pigmentation. AMM represents 2-8% of all malignant melanomas. This rare subtype is difficult to diagnose clinically as it mimics other benign skin lesions. AMM can occur in any part of the body with various presentations and has a predilection for male gender and fair skin tones. We present a case report of a 62-year-old Caucasian male with AMM of the right lower extremity. The patient presented with a painless nodule on his right lower extremity that rapidly increased in size for seven months with no signs of malignancy, such as fever, night sweats, fatigue, bruising, weight loss, or headache. Simultaneously, the patient presented with right inguinal lymphadenopathy and pitting edema of the right lower extremity. The patient had a previous medical history of basal and squamous cell carcinoma and psoriasis with no personal or family history of melanoma. The mass was excised and sent to a pathologist along with a right inguinal sentinel lymph node biopsy. The final pathology report revealed an ulcerated AMM on the right lower extremity and a positive node for melanoma with a metastatic deposit. The patient underwent adjuvant immunotherapy resulting in the clearance of the cancer cells. This report highlights the importance of early diagnosis, appropriate surgical management, and adjuvant therapy to improve the prognosis of this rare melanoma subtype.