Metastasis of a Dorsal Melanoma to a Pituitary Adenoma Mimicking Pituitary Apoplexy

Metastases to pituitary adenomas are very rare. From the 20 cases found in the literature, none originated from a cutaneous melanoma. We present the case of a 67-year-old man with a history of transcranial approach to treat a pituitary macroadenoma followed by adjuvant radiotherapy. Fifteen years later, he presented a dorsal nodular melanoma, and three years after that, he developed symptoms of pituitary apoplexy. He was submitted to transsphenoidal surgery, and the histology result revealed metastasis of the melanoma into a pituitary adenoma. The similarity in the clinical presentation of the two entities—pituitary apoplexy and metastasis of the melanoma into a pituitary adenoma—and the rarity of this type of metastization alert to challenges in the differential diagnosis that may confound the neurosurgeon's decision.