A case of retroperitoneal schwannoma showing high fluorodeoxyglucose uptake on positron emission tomography

Abstract

A 74-year-old woman was admitted to our hospital due to a retroperitoneal mass. Abdominal ultrasonography, CT and MRI demonstrated a solid tumor 8.0 cm in diameter in the dorsum of the right kidney. Since this tumor demonstrated high fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET), we could not rule out the possibility of malignancy. Laparotomy was thus performed under a preoperative diagnosis of retroperitoneal tumor. The pathological diagnosis was schwannoma, with a mixed formation of Antoni types A and B. Because schwannomas are among the benign tumors showing high FDG uptake on PET, we should recognize them when making a differential diagnosis versus malignant tumors.