Carcinoid tumour of the extrahepatic bile duct--report of a case and literature review.

Carcinoid tumors of the extrahepatic bile duct are rare and account for only 0.2-2% of all gastrointestinal carcinoids 1, CASE REPORT A 30 yr old man presented with obstructive jaundice while on holiday in Australia. Physical examination was otherwise normal. Abdominal ultrasound, CT scan and MRI scan confirmed marked dilatation of the intrahepatic biliary system. ERCP revealed a stricture in the common hepatic duct (Figure 1). A stent was inserted. Brush cytology was inconclusive. CA19-9 and CEA levels were normal. Following return to the UK, laparotomy was performed and revealed a 3cm tumour at the junction of cystic duct and CHD. Excision of the bile duct with portal lymphadenectomy and Roux-en-Y hepaticojejunostomy was performed. He had an uneventful postoperative course. Histopathology revealed a white firm tumour obliterating the lumen ofthe CHD. Microscopically, the tumour contained round and polygonal cells arranged in nests and separated by fibrous stroma. Tumour cells were tested for neuroendocrine markers incuding chromogranin S and serotonin, but were positive only for protein gene peptide and neurone specific enolase (Figure 2). Ultrastructural appearances on electron microscopy showed dense-cored neuroendocrine granules consistent with a mid-gut carcinoid tumour. Margins were free of tumour but one out of eleven lymph nodes showed a metastatic deposit. Postoperatively, gastrointestinal hormone levels including NeurokininA, Gastrin Release Peptide, and Pancreatic Polypeptide were normal. Daily urinary excretion of 5 hydroxyindoleacetic acid (5-HIAA) was also within the normal range. SPECT octreotide scan did not reveal any metastases and he remains well at follow up 18 months later. DISCUSSION Carcinoid tumours of the bile duct are rare. As with other tumors of the bile duct, these lesions are difficult to diagnose preoperatively and nearly impossible to distinguish from cholangiocarcinoma. They are derived from embryonal neural crest cells (Kulchitsky cells) and have the potential to produce serotonin3. These cells are also known as argentaffin cells, because of their affinity for silver staining compounds and are located in the crypts of Leiberkuhn. Most of the information about this malignancy is from case reports. A comprehensive search of Medline and Embase revealed forty two cases of carcinoid of the extrahepatic duct, including our case. In 1959, Davies first published a case of biliary carcinoid although this may have been a periampullary carcinoid4. Pilz has been credited with the first reported case of carcinoid of the biliary tract5. Clinical characteristics, pathology and follow up data of previously described cases are summarized in …