摘要：
目的 探讨不典型梭形细胞脂肪瘤样肿瘤(ASLT)的临床病理特征,免疫表型特点以及诊断和鉴别诊断要点.方法 收集2010年1月至2017年3月就诊于浙江省人民医院的3例ASLT患者资料,总结其临床和影像学特征、组织形态学、免疫组织化学表型以及预后情况,采用荧光原位杂交法检测MDM2基因扩增情况,结合相关文献进行讨论.结果 3例均为成年男性,年龄分别为38岁、43岁和54岁.1例累及头颈部皮下组织,1例位于左主支气管内,1例位于背部肩胛下方背阔肌内.肿瘤最大径4.0~5.8 cm,大体界限较清楚.镜下观察:3例均可见局灶的浸润性边界,由不同比例和数量的梭形瘤细胞和脂肪细胞组成,分布于多少不等的黏液样和纤维性基质之中,均可见散在聚集的脂肪母细胞;1例以梭形细胞成分为主,1例以脂肪细胞为主,1例两者分布较为均等.梭形瘤细胞大多数形态温和,1例局灶散在可见核增大和浓染,均未见核分裂象.免疫组织化学染色:3例梭形瘤细胞均弥漫表达CD34,1例显示明确的视网膜母细胞瘤蛋白表达丢失;脂肪细胞均表达S-100蛋白;INI-1表达均无丢失,Ki-67阳性指数1%~3%,其余标志物均阴性.2例肿瘤行MDM2基因荧光原位杂交检测均未见扩增.1例头颈部ASLT术后切缘阳性,随访17个月组织学检查证实复发2次;1例背部肩胛下方ASLT随访33个月,未见复发和转移;1例为新发病例,未随访.结论 ASLT是一种不同于不典型脂肪瘤样肿瘤/高分化脂肪肉瘤的少见类型的低度恶性脂肪肿瘤,形态学具有明显的异质性和连续的谱系,需要与多种良恶性软组织肿瘤区分.%Objective To investigate the clinicopathologic characteristics, immunophenotype, differential and diagnostic features of atypical spindle cell lipomatous tumor(ASLT). Methods Three cases of ASLT were collected from January 2010 to March 2017 at Zhejiang Provincial People's Hospital. The clinical and imaging features, histomorphology, immunophenotype and prognosis were analyzed. Fluorescence in situ hybridization(FISH)was used to detect MDM2 gene amplification, and relevant literature was reviewed. Results All three patients were adult males, aged 38, 43 and 54 years, respectively. One tumor originated in the subcutaneous soft tissue in the head and neck,one was located in the left primary bronchus and one in the latissimus dorsi muscle. Grossly, all three tumors were circumscribed and ranged from 4.0 to 5.8 cm in size. Microscopically,all showed a focally infiltrative front. These tumors were composed of variable proportions of spindle-shaped and adipocytic cells in a background of variable fibrous and edematous matrix. Scattered lipoblasts were easily seen. One tumor was composed predominately of spindle tumor cells,one of adipocytic cells,and one of equally mixed cell populations. The spindle tumor cells were generally bland-appearing with focal nuclear enlargement and hyperchromasia noted in one case. Mitosis was not seen in neither the spindle cells nor the adipocytic cells. By immunohistochemistry,diffuse and strong reactivity to CD34 of the spindle cells was noted in all cases, definite loss of Rb expression was noted in one of three cases, and S-100 protein was expressed only in the adipocytic cells. INI-1 was intact and Ki-67 index was 1% to 3%. All other markers including CDK4, MDM2,STAT6, SOX10, CD99, bcl-2, β-catenin, CD117, GFAP, CK, EMA, SMA and desmin were negative. FISH of MDM2 was done in two cases,and both showed no amplification. The ASLT in the head and neck had two recurrences during 17 months of follow-up,whereas the tumor in the latissimus dorsi was free of disease during 33 months of follow-up.Conclusions ASLT is a rare subtype of low-grade adipocytic neoplasm and is distinctive from atypical lipomatous tumor/well-differentiated liposarcoma. The histomorpholgy of ASLT has significant heterogeneity and forms a continuous spectrum. ASLT needs to be distinguished from a series of benign and malignant soft tissue tumors.
