Joldoshova Albina, Khandakar Binny, Lee Hwajeong, Lam Robert, Jain Dhanpat
Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
Department of Pathology and Laboratory Medicine, Albany Medical Center, Albany, NY, USA.
Hum Pathol. 2025 Sep;163:105879. doi: 10.1016/j.humpath.2025.105879. Epub 2025 Jul 24.
Extensive ductular proliferation can mimic well-differentiated cholangiocarcinoma, but such pseudo-tumorous lesion has not been well described in the literature. Our study sought to evaluate the clinicopathologic features of such cases.
Four cases with reactive ductular proliferation that mimicked cholangiocarcinoma microscopically and also appeared grossly to form a mass/nodule were identified from 1995 to 2024 at two large academic health institutions. The clinicopathological features were studied in detail.
The study cases included 2 explants, 1 segmental hepatectomy and 1 wedge resection. One of the explants had thrombosis and obstruction of the right portal vein (PV) along with right lobe atrophy. Vascular abnormality was suspected in case 2 but could not be confirmed. However, atrophy of the left lobe along with caudate lobe hypertrophy and preserved right lobe was observed. Both cases had cirrhosis (case 1: HCV infection, case 2: alcoholic liver disease) with portal hypertension. Case 3 and 4 were from patients with metastatic colon cancer who had undergone trans-arterial chemoembolization (TACE). Upon gross examination of the two explants, the atrophic lobes were markedly pale-tan, shrunken, and well-demarcated from the uninvolved lobe mimicking a tumor, while the unaffected lobes were cirrhotic. Histologically the lesions in all cases comprised of marked ductular proliferation that led to an initial consideration of a well-differentiated intrahepatic cholangiocarcinoma. However, these lacked significant cytologic atypia and mitotic activity (ki-67 < 5 %) and had a non-infiltrative growth pattern. In case 3, the ductular proliferation was at the periphery of metastatic focus, while scattered metastatic tumoral glands were encased within proliferating ductules in case 4. The immunostains showed wild-type staining pattern with p53 and retained nuclear expression with p16 and BAP1.
Biliary pseudo-tumors can be seen with lobar or segmental atrophy, likely secondary to ischemic parenchymal injury and can mimic a well-differentiated cholangiocarcinoma grossly as well as microsopically. Awareness of this phenomenon and careful attention to the clinical presentation, radiographic imaging and histology shows subtle differences that can facilitate an accurate diagnosis.
广泛的小胆管增生可酷似高分化胆管癌，但这种假肿瘤性病变在文献中尚未得到充分描述。我们的研究旨在评估此类病例的临床病理特征。
1995年至2024年期间，在两家大型学术健康机构中，共识别出4例反应性小胆管增生病例，这些病例在显微镜下酷似胆管癌，大体上也表现为形成肿块/结节。对其临床病理特征进行了详细研究。
研究病例包括2例肝外植体、1例肝段切除术和1例楔形切除术。其中1例肝外植体伴有右门静脉血栓形成和阻塞以及右叶萎缩。病例2怀疑有血管异常，但无法确诊。然而，观察到左叶萎缩伴尾状叶肥大，右叶保留。两例均有肝硬化（病例1：丙型肝炎病毒感染，病例2：酒精性肝病）伴门静脉高压。病例3和病例4来自接受过经动脉化疗栓塞术（TACE）的转移性结肠癌患者。对这2例肝外植体进行大体检查时，萎缩的肝叶明显呈淡黄褐色、萎缩，与未受累的肝叶界限清楚，类似肿瘤，而未受影响的肝叶为肝硬化。组织学上，所有病例的病变均由明显的小胆管增生组成，最初考虑为高分化肝内胆管癌。然而，这些病变缺乏明显的细胞异型性和有丝分裂活性（Ki-67<5%），且呈非浸润性生长模式。病例3中，小胆管增生位于转移灶周边，而病例4中，散在的转移瘤性腺管被增生的小胆管包绕。免疫组化显示p53呈野生型染色模式，p16和BAP1保留核表达。
胆汁性假肿瘤可伴有叶或段萎缩，可能继发于缺血性实质损伤，在大体和显微镜下均可酷似高分化胆管癌。认识到这一现象并仔细关注临床表现、影像学检查和组织学表现，可发现有助于准确诊断的细微差异。
