A case of ganglioneuroma presenting abnormal FDG uptake.

We report a case of ganglioneuroma with abnormal 18F-fluorodeoxyglucose (FDG) uptake. A 26-year-old woman presented to the hospital with a slowly growing abdominal tumor without symptoms. She was diagnosed with neuroblastoma in childhood and treated by surgery and chemotherapy. Computed tomography (CT) revealed huge retroperitoneal tumors and fused 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT image showed abnormal accumulation of FDG in tumors with maximal standardized uptake value of 2.02. Considering her past history, ganglioneuroma matured from neuroblastoma was considered, the most likely diagnosis. However, a second primary malignant tumor, such as malignant peripheral nerve sheath tumor arising in ganglioneuroma, could not be ruled out. Then, an excisional biopsy was performed and the diagnosis of mature ganglioneuroma was made. Pathological investigation may be needed to differentiate ganglioneuroma from other malignant tumors and, therefore, FDG-PET/CT findings can be helpful for biopsy planning.