Malignant gastrointestinal neuroectodermal tumour arising in the extrahepatic bile ducts; a rare neoplasm in an unusual anatomic location

• Published in: BMJ case reports 2022-07, Vol.15 (7), p.e250094
• Main Authors: Miller, C Quinn, Al-Hader, Ahmad, Vance, Gail H, Zhang, Chen
• Format: Article
• Language: English
• Subjects: Bile Duct Neoplasms - diagnosis; Bile Duct Neoplasms - pathology; Bile Duct Neoplasms - surgery; Bile ducts; Bile Ducts, Extrahepatic - pathology; Case reports; Cholecystectomy; Cytokeratin; Female; Gastrointestinal Neoplasms - pathology; Humans; Keratins - analysis; Liver; Liver cancer; Melanoma; Metastasis; Morphology; Neuroectodermal Tumors - genetics; Sarcoma; Surveillance; Tumors
• ISSN: 1757-790X; 1757-790X
• DOI: 10.1136/bcr-2022-250094

Malignant gastrointestinal neuroectodermal tumour (GNET) is a rare, aggressive neoplasm with fewer than 100 cases reported in the literature. Most cases arise in the tubular gastrointestinal tract. We reported a unique case of GNET arising in the extrahepatic bile ducts and reviewed the literature of GNETs. The patient is a female in her mid-30s who presented with painless jaundice and diarrhoea several months after cholecystectomy for biliary dyskinesia. Workup revealed a tumour arising from the peripheral 4B bile ducts involving the left hepatic duct and bifurcation. Histologic examination of the lesion showed a malignant spindled and epithelioid neoplasm which strongly expressed S100 and SOX-10. Neoplastic cells were negative for various cytokeratins and melanoma markers. FISH testing using break-apart probes showed rearrangement of the gene region. The immunohistochemical and molecular findings are consistent with a diagnosis of GNET arising in the extrahepatic bile ducts.