Magnetic resonance imaging features of choledochal traumatic neuroma

Objective To summarize magnetic the resonance imaging (MRI) features of choledochal traumatic neuroma, and investigate the key points of diagnosis and differentiation. Methods This was a retrospective descriptive study. The clinicopathological data of 1 patient with choledochal traumatic neuroma who was admitted to the Yantaishan Hospital on 18 August, 2015 were collected. The patient received pre-contrast and dynamic-contrast-enhanced MRI and MR cholangiopancreatography (MRCP). Observational indexes included: (1) imaging features: location, size, signal intensity and enhancement characteristics of the lesion; (2) treatment and prognosis: surgical treatment, pathological findings, results of immunohistochemical staining and clinical follow-up. After preoperative related examinations, the patient and relatives were willing to receive surgical therapy, and postoperative pathological examinations and immunohistochemical staining were conducted. The follow-up using outpatient examination was performed to detect the patient′s recovery and clinical symptoms up to January 2016. Ultrasound and laboratory examinations [alanine transaminase (ALT), aspartate transaminase (AST), γ-glutamyl transpeptidase (GGT) and total bilirubin (TBil)] were also recorded. Results (1) Imaging features: pre-contrast MRI revealed a stricture and intra-lumen nodular in the middle portion of common bile duct. The nodular was measured 1.2 cm×0.9 cm at maximum cross-section. The nodular was well-demarcated and homogeneous of hypointensity on T1-weighted image comparing to hepatic parenchyma, slight hyperintensity on T2-weighted image and slight hypointensity on fat-suppressed T2-weighted image. MRCP could demonstrate the nodular more clearly and dilation of distal bile duct and intra-hepatic bile ducts. The width of common bile duct was 1.4 cm. After administration of contrast materials, the nodular showed avid enhancement and delay enhancement, which was mild enhancement at the artery phase, and gradual increase at the portal vein phase and the delay phase. The length of central stricture of the common bile duct was 1.3 cm. There was no abnormal enhancement in liver, spleen and pancreas. No retroperitoneal lymphadenopathy could be seen. The imaging diagnosis was cholangiocarcinoma with dilation of bile ducts. (2) Treatment and prognosis: the patient received surgery for tumor resection and Roux-en-Y reconstruction. The removed gross specimen was a grey-white nodular measured 2.0 cm×1.0 cm. The cute surface was grey-white and stiff. The microscopic evaluation revealed haphazard arrangement of nerve bundles within the hyperplasia fibrotic stroma. Normal biliary epithelial cells can be seen beside the nerve bundles. Immunohistochemical staining showed S-100 and Vimentin were positive. The index of Ki-67 was 5%. The patient was discharged at 14 days postoperatively with the good recovery. During postoperative 5-month follow-up, the patient had good recovery and jaundice scleras were disappeared. Ultrasound showed the bile ducts were not dilated. The results of laboratory examinations were normal. Conclusion MRI features of choledochal traumatic neuroma include an intra-lumen nodular with biliary stricture and avid and delay enhancement after contrast materials administration. Key words: Traumatic neuroma; Biliary system; Magnetic resonance imaging