Uncommon neoplasms of the biliary tract: radiological findings.

OBJECTIVE: To report our cancer centre experience in the biliary tumours incidence other than cholangiocellular-carcinoma, emphasizing the radiological features.

METHODS: 197 patients with biliary disease undergoing Gd-EOB-DTPA-enhanced MRI were reviewed. Four radiologists evaluated retrospectively size, structure, anatomical site and signal intensity of lesions on MRI. Enhancement-pattern during the arterial-, portal- and late-phase on ultrasound, CT and MR study was assessed as well as the enhancement pattern during the hepatobiliary-phase on MRI.

RESULTS: 23 patients were selected. The lesion was intraductal in 5 cases, periductal in 14 and intrahepatic in 4. 16 lesions were solid, 5 uniloculated cystic and 2 complex cystic. In five patients the lesion was simple cyst, with a signal intensity in T1 weighted (T1W) and T2 weighted (T2W) similar to the gallbladder. In two patients with complex cystic lesion, the solid component was heterogeneously hypointense in T1 W, hyperintense in T2 W with a restricted diffusion. The solid component showed heterogeneous contrast-enhancement on CT, MR and ultrasound. The tumour was intrahepatic in two patients, with signal hypointense in T1 W and hyperintense in T2 W. Diffusion was restricted. The lesions showed heterogeneous contrast-enhancement. The periductal lesions were hypointense in T1 W, hyperintense in T2 W with restricted diffusion. The lesion showed progressive contrast-enhancement. Peribiliary melanoma was hyperintense in T1 W, hyperintense in T2 W with restricted diffusion and progressively contrast-enhanced.

CONCLUSION: Biliary tumours can have a wide spectrum of radiologic appearances and consequently represent a diagnostic challenge for the radiologist. Advances in knowledge: MRI is the technique of choice in diagnosing biliary tumours, including rare (non-CCC) tumours.