Metastatic melanoma to the pituitary gland

Metastasis to the pituitary gland is unusual, and occurs most often in patients with carcinomas of the breast or lung. Despite its propensity for spread to the brain, metastatic melanoma has rarely been described within the sella.

We report two cases of malignant melanoma pathologically confirmed within the pituitary, both metastatic from a primary site on the chest wall. In each patient, transsphenoidal resection of the tumor was incomplete and each received local radiotherapy after surgery.

One patient recurred quickly and developed brain metastasis as well. He died four months after resection of the pituitary metastasis, but the second patient survived six months without recurrence. As intrasellar metastasis portends widespread systemic disease and may be synchronous with parenchymal brain metastasis, survival in such patients is limited regardless of adjunctive therapy.

Such cases are likely to arise more commonly in future due to the increasing incidence of melanoma. Identifying them by imaging alone is difficult due to inconsistent signal characteristics on MRI (as shown by these cases) and the confusion introduced by any associated intratumoral hemorrhage.