Endocrine Abstracts

Introduction: Adrenal masses usually represent benign and nonfunctional adrenal adenomas however, primary or metastatic malignancy should also be considered. Discovery of an adrenal mass needs further evaluation in order to exclude malignancy and hormonal secretion. Primary adrenal melanoma is an extremely rare entity, while metastases of cutaneous melanoma to the adrenals occur much more often. We present a rare case of a possibly primary adrenal malignant melanoma with imaging and biochemical features of a phaeochromocytoma.

Case report: A 61-year-old male farmer was referred for evaluation of a mass in the right supraclavicular region and a left adrenal lesion. The patient had a history of a multifocal papillary and medullary thyroid carcinoma 3 years before presentation. Genetic analysis for RET mutations was negative. Laboratory tests revealed increased 24-h urinary dopamine and also increased serum calcitonin and neuron specific enolase. The adrenal lesion measured 88.5 mm on MRI, displayed inhomogeneous enhancement of the contrast agent and low diffusion rate. Both lesions appeared positive in In 111-Pentetreotide scintigraphy, while meta-iodo-benzyl-guanidine (MIBG) scintigraphy was negative. Pathologic examination of the resected right supraclavicular mass and left adrenal was consistent with malignant melanoma. Rough evaluation for a primary melanoma site was negative.

Conclusion: This is the case of a possibly primary adrenal malignant melanoma with imaging and biochemical features of a pheochromocytoma. Melanocytes and chromaffin cells share a common embryological origin and in melanoma tissue there is expression of tyrosine hydroxylase leading to production of DOPA and melanins. Although this case is very rare, and there are rigid diagnostic criteria for the diagnosis of primary adrenal melanoma, the differential diagnosis of a dopamine secreting adrenal mass should include primary or metastatic malignant melanoma in order to determine the best diagnostic approach to the patient and select the most appropriate surgical management.