Endocrine Abstracts

Introduction: RET germline mutation in codon 634 of exon 11 is one of the most frequent mutations of classical multiple endocrine neoplasia type 2A (MEN2A). Virtually all patients with classical MEN2A develop medullary thyroid carcinoma (MTC), which is often the first manifestation of the disease and usually occurs early in life. Pheochromocytomas (PHEOs) tend to be diagnosed several years later or simultaneously with the MTC.

Case report: The patient, a 45 year-old man, was referred to the Endocrinology outpatient department following a bilateral adrenalectomy, performed 2 months before, (Pheochromocytoma of the Adrenal gland Scaled Score: left =0, right =4) and the finding of a thyroid micro nodule in a neck ultrasonography. There was no familiar history of MEN2 neither of its components. The physical examination did not disclose particular signs namely skin alterations in the interscapular region. Laboratory tests revealed elevated calcitonin (63.47 pg/ml, n <2). CEA, calcium, phosphorus, parathyroid hormone and plasmatic metanephrines were within the normal range. Thyroid, ultrasound guided, fine needle aspiration cytology of a 7 mm nodule in the left lobe was negative. Genetic testing of the RET proto-oncogene identified the heterozigous pathogenic variant c.1901G>A (p.Cys634Tyr) in the exon 11. The patient was submitted to total thyroidectomy with bilateral central neck dissection. The histology revealed multifocal and bilateral MTC (biggest diameter - 10 mm).

Discussion: Although less common the PHEO can be the first manifestation of MEN2A. Moreover, MTC is not always the most aggressive component of the syndrome.