(5.03) Pituitary adenomas in the setting of multiple endocrine neoplasia type 1, The importance of screening for Pancreatic and Parathyroid tumors

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominantly inherited endocrine tumor predisposition syndrome, caused by germline heterozygous mutations in the MEN1 gene, located on chromosome 11q13. The three main manifestations of MEN1 (collectively known as the three Ps) are Parathyroid adenomas (primary hyperparathyroidism), duodenoPancreatic neuroendocrine tumors and anterior Pituitary adenomas. 

Case(s) Description :

A 50-year-old male with a medical history of Fatigue, Erectile Dysfunction and decreased libido presented to the office for evaluation of prolactinoma with low testosterone and increased prolactin. MRI showed a 3.9cm pituitary adenoma. The patient denied a family history of tumors in the adrenals, pancreas, stomach, or thyroid and confirmed family history of Pituitary adenomas. An initial prolactin level of 2468 was started treatment with cabergoline 0.5mg twice a week, and due to abdominal discomfort was decreased to 0.25mg twice a week. MRI at 3 months follow-up showed a significant size decrease to now 1.9 x 1.7 x 1.7 cm (from 2.4 x 3.9 x 3.9 cm). Serum calcium was elevated at 11.7mg/dL. no history of kidney stones, hematuria or fractures - in-office thyroid ultrasound notable for a right posterior 1.7cm mass suggestive of a parathyroid adenoma and Total testosterone improved from 42 to 195, clinically reports significant improvement in ED and libido but not entirely back to baseline. 4-month follow-up ERCP with FNA done on 1/2023 reported Pancreatic cyst, MEN sequencing was negative, and the patient has no clinical signs of insulinoma or gastrinoma (no stomach ulcers but notable gastritis), complications of Hyperparathyroidism reported by DEXA shows lumbar osteoporosis and US kidney shows right nonobstructive nephrolithiasis. The patient has PTH-dependent hypercalcemia with PTH of 453 and corrected serum calcium of 11.7 - the patient meets the criteria for parathyroidectomy and was referred to surgery.

Discussion :

Prompt recognition and treatment are vital to avoid MEN type 1 Syndrome complications. Although the progression of PHPT in the context of MEN1 is usually gradual, the optimal treatment remains parathyroidectomy, with favorable results in reducing the risk of kidney stones, fragility fractures, and cardiovascular morbidity, while it has also been demonstrated that it significantly improves bone mineral density and quality of life. For Pituitary adenomas, Cabergoline still the drug of choice to decrease size and manifestations like increased prolactin and decrease testosterone levels.(2) It is important to look for all the possible manifestations that MEN syndrome could have and give adequate treatment to avoid complications.