Introduction: Adrenal Incidentalomas (AI) are frequently encountered in clinical practice with radiological studies suggesting a frequency of 3% at 50 years rising to 10% in elderly. Majority of AI are non functional adenomas with malignant lesions quoted as less than 20% at most. We report a case of AI, which was found to a Melanoma on biopsy with no other primary site.
Case: An 84 year old gentleman was found to have a right suprarenal mass on ultrasound done for lower urinary tract symptoms. He was physically very fit and well and his past medical history included Benign prostatic hypertrophy, Glaucoma and Osteoarthritis. He underwent a CT which showed a 6.3 cm right adrenal mass with possible spread to right lung hilum. His case was discussed in the MDT and a biopsy of this lesion showed a Melanoma. He underwent dermatological assessment including biopsies, which did not pick up any melanoma. Endocrine workup showed the lesion was non-functional. Our current working diagnosis is a Primary adrenal melanoma (PAM) and he is undergoing Immunotherapy.
Discussion: Primary adrenal melanomas are rare entities with only about a couple of dozen reported in history. It has been suggested that they may arise from ectopic melanocytes from pluripotent neural crest cells. PAMs are usually larger, unilateral and asymptomatic. Our case underwent a biopsy due to the larger size and the coexistence of a hilar lesion. Carstens et al. proposed a criterion (unilateral, no history of melanomas, no removal of pigmented skin or eye lesions) to distinguish PAM from metastatic lesions. The main modalities of treatment include surgical resection with targeted therapy and immunotherapy. Survival rates are poor and mortality after surgery has been quoted as 100% within 2 years.