Usefulness of 18F-fluorodeoxyglucose positron emission tomography for assessment of tumorviability after resection of granulocyte-colony-stimulating-factor -Producing cholangiocarcinoma-a case report

Introduction and importanceGranulocyte colony-stimulating factor (G-CSF)-producing intrahepatic cholangiocarcinoma is rare. Surgical cases with postoperative clinical course have rarely been reported.Case presentationA 63-year-old woman complained upper abdominal pain. Computed tomography (CT) showed intrahepatic mass measuring 9 × 9 × 9 cm in the left lateral segment. ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed high uptake by the tumor, with diffuse uptake in the bone marrow. An extended left lobectomy was performed to achieve complete resection. Histopathological examination showed poorly differentiated adenocarcinoma with no lymph node metastasis. Immunohistochemical analysis revealed that tumor cells produced G-CSF. After chemotherapy with S-1 regimen at 10 months after the operation, CT and FDG-PET detected lymph node metastasis in the peri-duodenal area and left kidney metastasis, with no FDG uptake in the bone marrow. Serum G-CSF was normal. Combination chemotherapy with gemcitabine plus cisplatin was administered, and, 12 months after liver resection, metastases were enlarged and FDG uptake in the bone marrow was detected again. Serum G-CSF was elevated at 71.6 pg/mL. The patient was enrolled in a clinical trial of chemotherapy with another regimen and was alive at 19 months after liver resection.Clinical discussionBecause of rapid progression, rapid diagnosis and resection are important. FDG uptake in the bone marrow is characteristic in G-CSF producing tumor. In this case, FDG uptake in the bone marrow reappeared after the enlargement of recurrent lesions, followed by tumor enlargement.ConclusionFDG-PET was useful for differential diagnosis and to assess tumor viability and determine the surgical indication.