Endocrine Abstracts

Introduction: Multiple endocrine neoplasia type 1 (MEN 1) is associated with neoplasia and hyperfunction of the parathyroid and pituitary glands, pancreatic islet cells, and neuroendocrine cells of the gut. Many authors advocate routine subtotal or total parathyroidectomy and autotransplantation for these patients. Here we demostrate negative MEN1 and MEN4 gene mutation analysis in a case with prolactinoma and a large parathyroid adenoma that could not be localized with preoperative imaging techniques.

Case: A 21-year-old man applied with a 8 years history of recurrent renal stones and increased serum calcium (11.25 mg/dl [Normal–9-10.5mg/dL]), alkaline phosphatase (147 U/L [Normal-30-120U/L]), serum parathyroid hormone (137 pg/l[Normal–10-60pg/mL]) and low phosphorus (2.1 mg/dl[Normal 3–4.5mg/dL]). Localization studies by imaging techniques (neck ultrasonography, Computed tomography and Tc-99m MIBI scintigraphy) failed to determine the number and location of diseased parathyroid glands. In addition, laboratory studies demonstrated elevated serum prolctine (246, Normal - 4.79-25.3 ng/mL). Other pituitary hormones were normal. Pituitary magnetic resonance imaging revealed 7.5 mm pituitary adenoma. He was started on cabergoline. Germ-line mutation analysis for MEN1 and Multiple endocrine neoplasia type 4 (MEN4) genes were negative and he had no familial history of endocrine tumors. Intraoperative parathyroid exploration demostrated a 3 cm paratyhroid adenoma. Histopathpolohical diagnosis was compatiel with parathyroid adenoma. There was no hypocalcemia or recurrence with a follow-up of 14 months.

Conclusion: Coexistence of hyperparathyroidism and prolactinoma in a young patient might not be always related to MEN1. A careful intraoperative exploration by an experienced parathyroid surgeon can be the best approach when hyperparathyroidism is diagnosed biochemically despite negative localization.