[MRI features of lymphoepithelioma-like intrahepatic cholangiocarcinoma]

Objective: To investigate the MRI manifestations of lymphoepithelioma-like intrahep cholangiocarcinoma (LEL-ICC). Methods: MR images of 26 cases with LEL-ICC confirmed pathologically at Zhongshan Hospital Affiliated with Fudan University between March 2011 and March 2021 were retrospectively analyzed. The number, location, size, morphology, edges of lesions, non-scan signal intensity, cystic necrosis, enhancement mode, peak, and capsule, vascular invasion, lymph node metastasis, and other MR images were included for analysis. The apparent diffusion coefficient (ADC) value of the lesion and the surrounding normal liver parenchyma were measured. A paired-sample t-test was used to statistically analyze the measurement data. Results: All 26 cases of LEL-ICC had solitary lesions. Mass-type LEL-ICC was the most common [n=23, lesion size (4.02±2.32) cm] with distribution along the bile duct [n=3, lesion size (7.23±1.40 cm)]. Among the 23 lesions of mass type LEL-ICC, most of the lesions were close to the liver capsule (n=20), round (n=22), clearly bordered (n=13), and cystic necrosis (n=22). In the three lesions of LEL-ICC distributed along the bile duct, most of them were close to the liver capsule (n=2), irregular (n=3), blurred edges (n=3), and cystic necrosis (n=3). All 26 lesions showed a low/slightly low signal on T₁WI, a high/slightly high signal on T₂WI, and a slightly high or high signal on DWI. Three lesions showed fast-in and fast-out enhancement modes, and 23 lesions showed continuous enhancement. Twenty-five lesions showed peak enhancement in the arterial phase, and one lesion appeared in the delayed phase. The ADC value of 26 lesions and adjacent normal liver parenchyma was (1.112±0.274)×10^-3 mm²/s and (1.482±0.346)×10^-3 mm²/s, respectively, and the both had a statistically significant difference (P<0.05). Conclusion: Certain manifestations of LEL-ICC in magnetic resonance imaging are advantageous for diagnosis and differential diagnosis.