Synchronous GH- and prolactin-secreting pituitary adenomas

Summary

Pituitary adenomas are usually solitary lesions. Rarely, patients may present with two distinct pituitary tumors. We report a case of synchronous secretory pituitary adenomas in a woman who initially presented with elevated prolactin levels. She was initially treated with cabergoline, but, after many years, she began developing symptoms consistent with acromegaly. Imaging revealed two distinct tumors within the pituitary gland. Endocrinological investigation confirmed acromegaly. At the time of surgery, two separate tumors were identified and resected. Pathological analysis demonstrated one tumor as a prolactinoma, and the other tumor as a GH-secreting adenoma. Postoperatively, her GH and IGF1 levels normalized, while the prolactin level remained slightly above normal. This case highlights that GH and prolactin level elevation is not always from co-secretion by the same adenoma.

Learning points

• Synchronous pituitary adenomas represent <0.5% of pituitary tumors requiring surgery.

• In the setting of elevated GH and prolactin levels, one cannot assume that they are co-secreted by the same adenoma.

• A careful study of hormonal workup and pre-operative imaging is necessary for synchronous pituitary adenomas to assure resection of both tumors.