Atypical spindle cell/pleomorphic lipomatous tumor with a sarcomatous component showing high mitotic activity and Ki-67 labeling index: report of a unique case mimicking dedifferentiated liposarcoma
Atypical spindle cell/pleomorphic lipomatous tumor with a sarcomatous component showing high mitotic activity and Ki-67 labeling index: report of a unique case mimicking dedifferentiated liposarcoma
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DOI：
10.1007/s00795-022-00327-8
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发表时间：
2022-07-02
影响因子：
1.8
通讯作者：
Hasegawa, Tadashi
中科院分区：
文献类型：
--
作者：
Sugita, Shintaro;Sugawara, Taro;Hasegawa, Tadashi
非典型梭形细胞/多形性脂肪瘤（ASPLT）是一种新的良性脂肪细胞肿瘤，其组织学类型从脂肪细胞到梭形细胞/多形性肿瘤。后者的非脂肪细胞成分很少显示肉瘤的特征，尽管ASPLT被认为不会去分化。一例78岁女性左大腿ASPLT患者的肉瘤成分具有高有丝分裂活性和Ki-67标记指数（LI），类似于去分化脂肪肉瘤。脂肪细胞成分由各种大小的脂肪细胞和少量成脂细胞组成。肉瘤成分包括非典型梭形细胞的束状增生和散在的大型奇异和多核巨细胞。经常观察到有丝分裂像，包括非典型有丝分裂。免疫组化，肿瘤细胞呈分化簇34阳性，但小鼠双微体2同源物（MDM 2），细胞周期蛋白依赖性激酶4（CDK 4），或视网膜母细胞瘤（Rb）蛋白。肉瘤组织中Ki-67 LI达40%。荧光原位杂交结果显示，MDM 2和CDK 4基因未扩增，包括RB 1位点在内的13 q14缺失。患者在手术后3.5年仍然存活，没有局部复发或远处转移的证据。由于ASPLT可能表现出形态学变异，因此通过仔细的病理检查排除去分化脂肪肉瘤是很重要的。
Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a new entity of benign adipocytic tumor that spans a wide spectrum of histology from adipocytic to spindle cell/pleomorphic tumors. The latter non-adipocytic component rarely shows sarcomatous features although ASPLTs are not thought to dedifferentiate. A 78-year-old woman with ASPLT in the left thigh had a sarcomatous component with high mitotic activity and Ki-67 labeling index (LI) mimicking dedifferentiated liposarcoma. The adipocytic component consisted of various-sized adipocytic cells with few lipoblasts. The sarcomatous component consisted of a fascicular proliferation of atypical spindle cells with scattered large bizarre and multinucleated giant cells. Mitotic figures including atypical mitoses were frequently observed. Immunohistochemically, the tumor cells were positive for cluster of differentiation 34 but not mouse double minute 2 homolog (MDM2), cyclin-dependent kinase 4 (CDK4), or retinoblastoma (Rb) protein. Ki-67 LI in the sarcomatous component reached 40%. MDM2 and CDK4 genes were not amplified and 13q14 including the RB1 locus was deleted according to fluorescence in situ hybridization. The patient is alive with no evidence of local recurrence or distant metastasis 3.5 years after surgery. As ASPLT may exhibit morphological variation, it is important to rule out dedifferentiated liposarcoma with careful pathological examination.