ODP538 A Case of Multiple Endocrine Neoplasia Type 2A with Malignant Paraganglioma

: Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), pheochromocytoma/paraganglioma and primary hyperparathyroidism. CASE PRESENTATION: At the age of 54, the patient became aware of a thyroid mass and went to the hospital. She was diagnosed as MTC by cytology. She was referred to our hospital for treatment. No thyroid cancer patients were found in her relatives. Her thyroid gland was elastic and soft, and a hard nodule about 1.5 cm in the lower pole of her left thyroid lobe was found. An Ultrasonography found the multiple nodules in both lobes of the thyroid gland, suggesting multiple or metastases of MTC. Although there was no family history, MEN2 was suspected, and screening of the abdominal organs by a CT scan revealed a 35 mm nodular lesion with calcification on the ventral side of the inferior vena cava (IVC). Multiple neoplastic lesions were found in her liver S2, S6 and S8 region. A CT scan also found the overall thickened right adrenal gland. An MIBG scintigraphy showed abnormal accumulations in these lesions. Laboratory data showed the increased the catecholamine metabolites both in blood and urine, and slightly increased CEA and calcitonin levels in the serum. After the genetic counselling, an informed consent was obtained and genetic test of RET oncogene was performed. A germline mutation was found in codon 634. Based on these findings, we diagnosed her as MEN2A with MTC, malignant paraganglioma and multiple liver metastases. First, IVC ventral lesions, multiple hepatic lesions, and right adrenal gland resection were performed. One month after the operation, total thyroidectomy and cervical lymph node dissection were performed. Pathologically, the IVC ventral tumor was a ganglion tumor covered with a pseudocapsule, with fibrous vitrification and coarse calcification inside. The histology of the liver regions were almost the same, and there was no finding suggesting the metastasis of MTC, and the histological image was consistent with the liver metastasis of paraganglioma. The right adrenal gland was diagnosed with adrenal medulla hyperplasia. Since then, she has been receiving continuous Cyclophosphamide Hydrate/ Vincristine Sulfate/Dacarbazine chemotherapy, and at the end of the 24th course, she has progressed without recurrence or the appearance of new metastases. It was reported that most Paragangliomas and pheochromocytomas in MEN2 with RET germline mutation are characterized by nonaggressive behavior, and paraganglioma was thought to be rare in onset than pheochromocytoma in MEN2A. In particular, cases of malignant paraganglioma in MEN2 with the RET634 germline mutation are extremely rare. Presentation: No date and time listed