An 80-year-old man presented with progressive fatigue. Blood tests showed that serum calcium was increased (2.93 mmol/l, normal range 2.20-2.55 mmol/l) and serum concentration of intact parathyroid hormone (iPTH) inappropriately high (198 pg/ml, normal range 15-85 pg/ml). Neck ultrasonography and Tc-MIBI scintigraphy revealed a right parathyroid adenoma and a multinodular goiter. Serum calcitonin was significantly increased (220 pg/ml, normal range<10 pg/ml). Concomitantly, a chest-abdominal computed tomography was performed and revealed a 22 mm right adrenal incidentaloma. The urinary catecholamines and metabolites were two-fold above the upper limit of normal. After right adrenalectomy which confirmed the diagnosis of pheochromocytoma, the patient underwent total thyroidectomy with dissection of the central lymph node compartment and right parathyroidectomy. On histopathologic examination, both thyroid lobes presented 13 foci of MTC without lymph node metastasis and the parathyroid gland presented a benign adenoma without hyperplasia. The patient underwent screening and genetic testing revealing a germ line C634 G RET mutation. The diagnosis of Men2a at the age of 80 years and the absence of lymph node metastasis of the multiple MTC in a carrier of C634G mutation were unusual and argued for the possible role of genetic modifier(s) in this MEN 2a patient.