肝血管平滑肌脂肪瘤的形态学变异和免疫组织化学特征

目的探讨肝血管平滑肌脂肪瘤(AML)的临床病理学和免疫组织化学特征、诊断和鉴别诊断要点。方法对44例手术切除肝AML的临床病理学特征进行详细分析,并对10种免疫组织化学标志物的表达状况进行检测。结果肿瘤由平滑肌细胞、厚壁血管及脂肪3种成分混合组成,根据瘤组织成分的比例可分为经典型(13例)、肌细胞为主型(25例)、脂肪细胞为主型(4例)、血管瘤型(2例);肌细胞可呈多种形态变异,主要有上皮样细胞型、中间细胞型、梭形细胞型、嗜酸细胞型和多形细胞型5种;8例可见髓外造血。免疫组织化学染色显示,瘤细胞呈HMB45(44／44,100％)、SMA(38／38,100％)和CD117(30／38,78．9％)阳性。结论肝AML形态学变异较大,容易造成误诊,HMB45阳性瘤细胞具有重要的诊断意义,CD117可作为诊断AML的一个有用的辅助标记物。

Morphologic variants and immunohistochemical features of hepatic angiomyolipoma

Objective To study the clinicopathological characteristics, immunohistochemical features and differential diagnosis of hepatic angiomyolipoma (AML). Methods The clinicopathological features of hepatic AML were systematically examined in 44 surgically resected tumor specimens, with additional immunohistochemistry study using 10 relevant antibodies. Results The tumors were composed of various amounts of three components,i.e. blood vessels, smooth muscle cells and adipose cells. According to the proportions of each of these tissue components, AML was subcategorized into the classical type (n=13), myomatous type (n=25), lipomatous type (n=4), and angiomatous type (n=2). Myoid cells displayed various morphology, including epithelioid, intermediate (ovoid or short spindle), spindle, oncocytic, and pleomorphic features. Hematopoietic elements were present as minor findings in eight tumors. Immunohistochemically, the tumor cells were strongly positive for HMB45 (44/44,100%), SMA(38/38,100%) and CD117(30/38, 78.9%). Conclusions A correct diagnosis of hepatic AML might be difficult due to its various growth patterns and cell types. HMB-45 positivity in the myoid cells is a key feature for hepatic AML. CD117 may be another useful ancillary marker for reaching a definite diagnosis.