A Rare Combination: Multiple Endocrine Neoplasia Type 1 and Follicular Thyroid Carcinoma

Introduction Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-dominant hereditary syndrome associated with pituitary, parathyroid, and enteropancreatic endocrine tumors. Its estimated prevalence ranges from 1 in 10,000 to 100,000 (1). The syndrome arises from mutations of a putative tumor suppressor gene at chromosome 11q13 which encodes a 610amino acid protein, menin. Although the cellular and biochemical functions of menin are not well-known, loss of heterozygosity of the MEN1 locus appears in MEN1-related tumors (2). Patients with MEN-1 inherit an inactivated copy of MEN-1 in all cells; a second inactivation occurs postnatally in certain cells and neoplasia results from clonal expansion of the cells with dual inactivation (3). Abstract Multiple endocrine neoplasia Type 1 (MEN-1) is an inherited syndrome characterized by the development of endocrine tumors of the pancreas, parathyroid, and pituitary glands. Mesenchymal tumors and adrenal neoplasms might also accompany this syndrome. However, the syndrome is rarely associated with thyroid tumors in contrary to the multiple endocrine neoplasia Type 2 that includes medullary thyroid carcinoma. This case study presents a 44-year-old woman who was diagnosed with MEN-1 on the basis of her clinical characteristics, laboratory data, and the presence of endocrine tumors. Follicular thyroid carcinoma was detected in the patient when she was being operated for nodular goiter, 12 years ago. We report this rare case which is likely the third case in the available scientific literature.