Familial pituitary tumor syndromes.

Objective: To summarize current knowledge on the clinical and genetic characteristics of familial pituitary tumor syndromes.

Methods: This review is based on a comprehensive search through the English-language literature with use of the following terms: "familial," "pituitary," "adenomas," and "tumors."

Results: Familial pituitary tumors are rare and constitute approximately 5% of all pituitary adenomas. Currently, there are 4 recognized inherited syndromes that involve pituitary tumorigenesis-multiple endocrine neoplasia type 1 (MEN 1), multiple endocrine neoplasia type 4 (MEN 4), Carney complex (CNC), and familial isolated pituitary adenomas (FIPA). MEN 1 and CNC have been known for several decades, and their clinical and molecular characteristics have been comprehensively studied. Many familial cases of pituitary adenomas can be attributed to mutations in MEN1 and PRKAR1A genes. The recently defined MEN 4 is extremely rare. Familial pituitary tumors that are not associated with MEN 1 and CNC have been united under a new term introduced in the 1990s-FIPA. About 15% to 25% of patients with FIPA harbor mutations in the AIP gene.

Conclusion: Although rare, familial pituitary tumors present an opportunity to study inherited molecular and genetic mechanisms of pituitary tumorigenesis. A comprehensive understanding of their characteristics may provide a basis for early diagnosis and better management of affected patients.