Intrahepatic cholangiocarcinoma is a rare malignancy that originates from the epithelial cells of the intrahepatic bile ducts. Intrahepatic cholangiocarcinoma can metastasize in lymphatic chains, including the hepatoduodenal ligament, and it often invades adjacent organs or metastasizes to other visceral organs such as the lungs, bones, adrenal glands, and brain. However, distant skeletal muscle metastasis is very rare. Moreover, a metastatic skeletal muscle tumor rarely shows specific symptoms, making it difficult to identify in a routine examination. A 45-year-old man with a chief complaint of right upper quadrant abdominal pain was admitted to our hospital. Abdominal ultrasound and computed tomography with contrast enhancement showed a malignant mass in the right hepatic lobe, and 2-[18F] fluoro-2-deoxy-D-glucose positron-emission tomography revealed distant skeletal muscle metastases in the thorax and buttock. The patient underwent an ultrasound-guided percutaneous needle biopsy for the metastatic low-echo masses in the skeletal muscle.
Bile Duct Neoplasms/diagnosis/radionuclide imaging/secondary ; Cholangiocarcinoma/diagnosis/radionuclide imaging/secondary ; Fluorodeoxyglucose F18/*diagnostic use ; Humans ; Liver Neoplasms/*diagnosis/pathology/radionuclide ; Male ; Middle Aged ; Muscle Neoplasms/diagnosis/*radionuclide imaging/secondary ; Positron-Emission Tomography ; Radiopharmaceuticals/*diagnostic use ; Tomography, X-Ray Computed

Small cell carcinoma is usually seen in the lung, but rarely involves the gastrointestinal tract including biliary tract. A 65 year-old man was admitted because of obstructive jaundice. A smooth-surfaced round intraluminal mass with proximal bile duct dilatation was seen in the proximal common bile duct on endoscopic retrograde cholangiogram. Under the diagnosis of bile duct cancer, pylorus-preserving pancreatoduodenectomy was done. Pathology revealed a 2 cm sized small cell carcinoma in the proximal common bile duct and distal common hepatic duct. On immunohistochemical stain, the tumor cells were positive for neuroendocrine markers CD56 and synaptophysin. After surgery, the patient received 5 cycles of adjuvant chemotherapy with VIP (etoposide, ifosfamide, and cisplatin) regimen. However, the patient died of liver metastasis 12 months after the diagnosis. We report a case of extrapulmonary small cell carcinoma arising from the common bile duct.
Aged ; Bile Duct Neoplasms/complications/*diagnosis/surgery ; Carcinoma, Small Cell/complications/*diagnosis/surgery ; Cholangiopancreatography, Endoscopic Retrograde ; *Common Bile Duct/radiography/radionuclide imaging/surgery ; Fatal Outcome ; Humans ; Liver Neoplasms/diagnosis/secondary ; Male ; Positron-Emission Tomography ; Tomography, X-Ray Computed