Neuroendocrine tumor of the common bile duct: A case report of extremely rare cause for obstructive jaundice

Abstract

Introduction: Neuroendocrine tumors (NET) of common bile duct are rare. There have been less than 100 cases reported worldwide.

Presentation of case: A 37-year-old female patient was referred to our center after six months of abdominal pain with no definite diagnosis. At initial presentation, she complained of increased abdominal pain, nausea, vomiting, oral intolerance to food and icteric sclera. Physical examination and laboratory tests were indicative of pancreatitis. At day four, she took retrograde cholangiopancreatography (ERCP) and a mid CBD stenosis or impacted stone was found. In order to locally investigate the lesion, Endoscopic Ultrasound (EUS) examination was performed which reported 16 × 12 mm isoechoic tumoral lesion at the middle of the CBD. In this regard we decided to perform ERCP-guided brushing biopsy of the lesion. The pathology report was highly suggestive for malignancy. She underwent resection of the mid portion of the CBD with Roux-en-Y hepaticojejunostomy, cholecystectomy and portahepatis lymph node dissection. The pathology report indicated that the CBD lesion was well-differentiated neuroendocrine tumor grade II.

Discussion: The exact etiology of developing NET in the bile duct tissues is not clear however cholelithiasis and congenital malformation of the biliary tract has been proposed to cause chronic inflammation with subsequent metaplasia which ultimately transforms into NET.

Conclusion: As there are very few cases of NETs of the CBD, no definite surgical or medical treatment is proposed. Currently, combination of radical surgical resection and lymph node dissection followed by chemotherapy is the treatment of choice.

Keywords: Case report; Common bile duct; Neuroendocrine tumors.

Fig. 1

Magnetic resonance cholangiopancreatography images of common bile duct (CBD). Dilated proximal CBD measuring 12 millimetr is evident. The arrow shows filling defect in mid CBD.

Fig. 2

Computed Tomography scan images of the common bile duct. Histologic features of well differentiated neuroendocrine tumor of CBD: A, B: Bile duct wall is infiltrated by tumor (H&E, 100×, 100×). C: Tumor cells show mild cytologic atypia, round to oval nuclei, stippled chromatin and eosinphilic to clear cytoplasm (H&E, 400×). Immunohistochemical study of well differentiated neuroendocrine tumor of CBD: D,E: Immunohistochemical staining with Synaptophysin and Chromogranin is diffusely positive (IHC, 400×, 400×). F: KI-67 is positive in about 8 percent of tumoral nuclei (IHC, 100×).