A rapidly evolving carcinoma of the thymus discovered in a patient with multiple endocrine neoplasia type 1 and operated on for primary hyperparathyroidism

Introduction Thymic neuroendocrine (NE) tumors associated with multiple endocrine neoplasia type 1 (MEN-1) are rare, variably documented in 1–8% cases. They are malignant and aggressive tumors and constitute a major cause of mortality in MEN-1. We report here a case of neuroendocrine carcinoma of the thymus rapidly developing after parathyroidectomy in a patient with MEN-1. Case A 45-year-old man was admitted for headaches. He had hypercalcemia, a hypophosphatemia and high PTH. Imaging procedures favor parathyroid tumor and pituitary adenoma with slightly high prolactinemia = 1768 mU/mL. Abdominal MRI, FDG PetScan, and scintigraphy with octreotide completed the evaluation. A tumor of the thymus with a necrotic and atypical aspect and high metabolic activity without evidence of metastases was observed, together with 5 pancreatic and small bilateral adrenal nodules. The patient was operated on: in the same time resection of a retrotracheal parathyroid adenoma and of a malignant thymoma type P3 with invasion of pericardium and mediastinal fat, finally pituitay adenomectomy. Surgery was completed by mediastinal radiotherapy. Genetic evaluation confirmed MEN 1. Comment and conclusion NE tumors of thymus in MEN-1 are more common in males and smokers, quite always hormonally inactive, and incidentally diagnosed. They are malignant, aggressive tumors and are widely invasive and metastatic at presentation (affecting usually bone). They traditionally never are the initial feature of MEN-1, and almost always occur after hyperparathyroidism, thus providing an opportunity for prophylaxis at the time of parathyroid surgery. Usually tumors of the thymus occur 15–20 years after discovering g of MEN1. In contrast in our patient, the malignant tumor of the thymus was rapidly developed, that does not exclude precession of an unrecognized primary hyperparathyroidism.