p.L105Vfs mutation in a family with thymic neuroendocrine tumor combined with MEN1: a case report

Abstract

Background: Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder arising from mutations of the MEN1 tumor suppressor gene on chromosome 11q13; MEN1 is characterized by the development of neuroendocrine tumors, including those of the parathyroid, gastrointestinal endocrine tissue and anterior pituitary. Additionally, thymic neuroendocrine tumors in MEN1 are also rarely reported. Case presentation: This case report observed a family that presented with MEN1 p.L105Vfs mutation, and two of the family members had been diagnosed with thymic neuroendocrine tumor combined with MEN1. To the best of our knowledge, this is the first time such a mutation in the MEN1 gene has been reported. The proband presented with thymic neuroendocrine tumor, parathyroid adenoma and rectum adenocarcinoma. The son of the proband presented with thymic neuroendocrine tumor, gastrinoma, hypophysoma and parathyroid adenoma. Genetic testing revealed the frameshift mutation p.L105Vfs, leading to the identification of one carrier in the pedigree (the patient's younger sister). The proband then underwent parathyroidectomy at the age of 26 years (in 1980) for a parathyroid adenoma. Subsequently, the patient underwent thymectomy, radiotherapy and chemotherapy. The patient is now 64 years old, still alive and still undergoing Lanreotide therapy. Conclusion: Thymic neuroendocrine MEN1 is rare, but it accounts for almost 20% of MEN1-associated mortality. Consequently, we should focus on regular clinical screening of the thymus in MEN1 patients.

Thymic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1

“…Somatic MEN1 mutations have been reported in tumor samples from patients with sporadic TNETs, but have not previously been found in tumor samples of MEN1-associated TNETs [ 6 , 13 , 26 , 34 ]. However, a MEN1 mutation was recently reported in a tumor sample of TNET in a MEN1 family [ 35 ] and also in a recent larger study of MEN1-TNETs patients [ 36 ]. In two of our patients (#2, #4), we have previously shown that there was no loss of heterozygosity (LOH) in the MEN1 region in 11q13 [ 6 ].…”