¹²³I-MIBGシンチグラフィーが偽陽性像を示した副腎癌の1例

Abstract

A 59-year-old woman presented with a left adrenal tumor 4 cm in diameter. The ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy showed apparent accumulation in the left adrenal tumor. However, the patient had no sign or symptoms suggesting pheochromocytoma. No biochemical evidence of catecholamine excess was noticed. Computed tomography (CT) revealed relatively strong enhancement in the arterial phase, which persisted until the portal phase. The computed tomography (CT) and magnetic resonance imaging showed 2 liver nodule suspected to be metastatic tumors. No ¹²³I-MIBG accumulation was seen in these nodules. CT also showed thyroid nodules with calcification, which suggested papillary thyroid cancer. Based on the findings, open left adrenalectomy, partial hepatectomy and segmentectomy were performed under the clinical diagnosis of pheochromocytoma and metastatic liver tumors. Histopathological diagnosis was adrenocortical cancer. There was only lymphocyte infiltration in the liver nodules. Postoperative recovery was uneventful, and the patient underwent partial thyroidectomy 6 months later. The pathological diagnosis was papillary thyroid cancer. She has been without recurrence or metastases for 18 months after adrenalectomy. We found only 6 cases of MIBG scintigraphy-positive adrenocortical cancer in the literature. The mechanisms for MIBG uptake in adrenocortical cancer are discussed with a review of the literature.