Primary hepatic tumors with myxoid change: morphologically unique hepatic adenomas and hepatocellular carcinomas. Am J Surg Pathol, 2015,39(3):318-24.

Mucin production in primary liver neoplasms is typically interpreted as evidence for biliary differentiation. However, we have observed benign and malignant liver tumors that have abundant extracellular myxoid/mucinous material, yet have only evidence of hepatocellular differentiation. To further characterize these unusual findings, 9 cases were identified and further studied. Four cases were hepatic adenomas, whereas 5 were hepatocellular carcinomas. Extracellular myxoid/mucinous material was diffuse in 7 cases and patchy in 2 cases. The extracellular myxoid/mucinous material was typically weakly mucicarmine positive (N=6) and Alcian blue positive (N=8). All tumors were well differentiated, and none had evidence for biliary differentiation by morphology or immunohistochemistry. The hepatic adenomas arose in nondiabetic and nonobese patients. Both the hepatic adenomas and the hepatocellular carcinomas were strongly and diffusely HepPar1 positive, CK19 negative, and showed loss of LFABP protein expression. These findings indicate that extracellular myxoid/mucinous material in isolation should not be interpreted as cholangiocarcinoma. Furthermore, the unique morphology, the clinical characteristics, and the immunophenotype results suggest that myxoid hepatic adenomas and hepatocellular carcinoma may be unique tumor variants.

原发性肝脏肿瘤中，如果有粘液产生被认为是向胆道分化最直接的证据。然而，作者观察到在良性和恶性的肝脏肿瘤中，都可有丰富的细胞外粘液产生，而这些肿瘤仅有向肝细胞分化的依据。为了进一步描述这种不同寻常的发现，作者发现了9例类似的病例并对其进行了进一步的研究，其中4例为肝脏腺瘤，5例为肝细胞性肝癌。细胞外粘液样基质在7例中是弥漫的，2例中是局灶性的；6例中细胞外粘液样基质粘液卡红染色弱阳性，8例阿辛兰染色阳性。9例全为高分化肿瘤，在形态学及免疫表型上均无向胆道分化的依据。肝脏腺瘤的患者既非糖尿病患者，也非肥胖型患者。HepPar1在这9例中均弥漫阳性表达，而CK19均阴性；并且显示了LFABP蛋白表达的缺失。这些研究指出：细胞外粘液产生不应该单一的解释为胆管细胞癌，而且，从独特的形态学特征、临床特点及免疫表型结果来看，粘液样肝脏腺瘤和肝细胞性肝癌可能是一种独特的肿瘤变异亚型。