A 51-year-old man with no significant past medical history presented with a 3-day history of nausea and vomiting and 1 month history of jaundice. He had presented to an outside hospital 1 month prior with a bilirubin of 10 mg/dL, increased liver function test values, and an increased white blood cell count. He was determined to have obstructive jaundice. He underwent an endoscopic retrograde cholangiopancreatography, which showed an irregular mass in the common bile duct, and biopsy suggested a neuroendocrine tumor but was not definitive. An endostent was placed to relieve the obstruction caused by the mass. The patient was transferred to the University of Texas Medical Branch, where he underwent a magnetic resonance imaging/magnetic resonance cholangiopancreatography (MRCP). The MRCP showed an intraluminal mass in the common bile duct with likely extension into the neck of the gallbladder (Fig. 1). An abdominal and pelvic computed tomography (CT) was obtained, which confirmed the presence of an obstructing mass in the common bile duct and the neck of the gallbladder. Lesions elsewhere in the abdomen and pelvis were not identified, making metastasis unlikely. The patient was scheduled for surgical resection. After undergoing an appropriate bowel preparation, the patient underwent successful resection with pylorus-preserving pancreaticoduodenectomy. The patient’s postoperative course was complicated by a pancreatic fistula. The fistula was controlled by his operatively placed drains and was managed conservatively. He was discharged home on postoperative day 14. His pancreatic fistula drain was removed at his 2-week followup visit without further incident. The tumor was extremely poorly differentiated. Immunohistochemical stains were positive for EMA, BCL2, CD99, Ck 19, and AE1/AE3 and were negative for the smooth muscle stains S-100, CD45, myogenin, TTF-1, desmin, CAM 5.2, and CK 7 (Fig. 2a–c). This pattern of staining is consistent with a high-grade, poorly differentiated monophasic synovial cell sarcoma. The primary tumor was present in the common bile duct with extension into the gallbladder lumen. Three out of 10 lymph nodes were positive for the tumor. A search was performed for a different primary site of the tumor in our patient, and none was identified. He was determined to have a synovial cell sarcoma primary to the common bile duct. Nothing is known regarding the prognosis of synovial cell sarcoma primary to the common bile duct/gallbladder. As such, there is no standardized therapy. Based on the treatment of synovial cell sarcoma at other primary sites, adjuvant radiation was recommended. He has completed his J Gastrointest Surg (2008) 12:609–611 DOI 10.1007/s11605-007-0260-6