Introduction: Mortality in MEN1 results disproportionately from metastatic neuroendocrine tumors yet pituitary involvement remains a significant source of morbidity and mortality. Several reports have categorized the incidence, clinical features, pathology and outcome of pituitary disease in MEN1 patients but it remains unclear whether there are significant differences in MEN1-related pituitary tumors versus sporadic tumors. This study aimed to characterize the secretory patterns, size, degree of local invasion, frequency of recurrence and the need for adjuvant treatment in MEN1-related pituitary tumors.

Methods: A departmental database was used to identify MEN1 patients treated surgically for pituitary tumors between 1985 and 2014 yielding 22 patients of 173 total MEN1 patients.

Results: Overall 18 (82%) tumors were functional while 4 (18%) were nonsecreting. Among secreting adenomas were 13 (59%) prolactinomas; 4 (18%) GH-secreting tumors and 1 (4.5%) ACTH-secreting tumor. Multihormonal secretion was present in 3 (14%) patients. The mean age for prolactinomas was 26.0 ± 1.8 versus 35.7 ± 3.3 for tumors overall. The average age for patients treated for nonsecreting tumors was 58.3 ± 2.8. Prolactinomas were 5 times less likely to be a macroadenoma than other tumor types. No tumor showed signs of malignant degeneration. Complications included CSF leak (23%) and pituitary failure (18%). Recurrent tumors in 3 patients were treated with repeat transsphenoidal surgery, radiation therapy and open resection. Adjuvant radiation was used in 3 (14%) patients.

Conclusions: MEN1-related pituitary tumors are unlikely to represent a distinct pathophysiological entity. Prolactinomas were over-represented among MEN1-related pituitary tumors and occurred at younger ages and were smaller on presentation. This is likely due to the fact that prolactinomas are drawn to clinical attention sooner due to hyperprolactinemia resulting in amenorrhea and galactorrhea. Adequate pharmacotherapy has also limited surgical intervention. MEN1-related pituitary tumors were not more aggressive or invasive than sporadic tumors.

Patient Care: This data will help in counseling MEN1 patients regarding the pituitary disease-specific prognosis and optimal management.

Learning Objectives: To review the genetic etiology and clinical manifestations of multiple endocrine neoplasia type 1. To understand differences in pituitary tumors occurring sporadically versus those occurring in the context of MEN1.

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