Hepatic Recurrence of Neuroendocrine Tumor Component in Gallbladder Cancer

A 60-year-old man underwent an extended cholecystectomy with regional lymphadenectomy for T2N0M0 gallbladder cancer (GBC), which showed significant FDG uptake (SUV max = 6.5). However, CT scan at 24 months postsurgery revealed multiple hepatic masses. Unlike the primary GBC, the hepatic masses showed limited FDG uptake (SUV max = 3.7). A tumor biopsy revealed the diagnosis of a grade 3 neuroendocrine tumor. Furthermore, the hepatic masses showed significant uptake on somatostatin receptor scintigraphy. Upon reevaluation, the primary resected specimen was found to include approximately 10% of neuroendocrine tumor components. This case suggests that different FDG uptake between primary and metastatic cancer may necessitate differential diagnosis.