2020年WHO分类软组织肿瘤病理学新进展(4)

付刚8bid499jz5 2020-09-18

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Inflammatory Leiomyosarcoma	炎症性平滑肌肉瘤
Inflammatory leiomyosarcoma is a rare low-grade sarcoma that was originally buried within the “inflammatory malignant fibrous histiocytoma” wastebasket, and previously included as a variant of leiomyosarcoma (in the fourth edition of the WHO Classification); owing to marked differences in clinical behavior and genetics, inflammatory leiomyosarcoma has now been designated a separate entity in the fifth edition. Inflammatory leiomyosarcoma has a peak incidence in young adults and occurs in the soft tissues of the extremities and trunk.	炎症性平滑肌肉瘤是一种罕见的低度肉瘤，最初放在“炎性恶性纤维组织细胞瘤”废纸篓内，先前被归类为平滑肌肉瘤的变异型（WHO分类第四版）；由于临床行为和遗传学的不同，在第五版中，炎症性平滑肌肉瘤作为一个单独的实体。炎症性平滑肌肉瘤高峰年龄为年轻成人，好发部位为四肢和躯干的软组织。
The histologic features are notable for a prominent inflammatory infiltrate obscuring the neoplastic cells, comprised of foamy histiocytes and prominent lymphocytes; the tumor cells are arranged in fascicles and are typically relatively uniform with mild atypia and eosinophilic cytoplasm (Fig. 6).	组织学特征为明显的炎性浸润掩盖肿瘤细胞，炎症细胞由泡沫样组织细胞和显著的淋巴细胞组成；呈束状排列的肿瘤细胞相对一致，有轻微的异型性和嗜酸性细胞质（图6）。
Cytogenetic studies have identified a distinctive characteristic near-haploid genotype, with or without subsequent whole genome doubling.	细胞遗传学研究已经证实具有独特的特征，接近单倍体基因型，有或没有随后的全基因组加倍。
Gene expression studies have also identified a distinct signature with prominent expression of genes involved in muscle development and function.	基因表达研究还发现了一个明显的特征，即肌肉发育和功能相关基因的显著表达。
The differential diagnosis can present a challenge in these cases due to the striking inflammatory infiltrate, with some histologic resemblance to other tumors including inflammatory myofibroblastic tumor and DDLPS, as well as idiopathic mass-forming disorders such as sclerosing mesenteritis, idiopathic retroperitoneal fibrosis, and IgG4-related disease (depending upon the anatomic site).	由于明显的炎性浸润，与其他肿瘤的组织学相似，包括炎性肌纤维母细胞瘤和DDLPS以及特发性肿块形成障碍，如硬化性肠系膜炎、特发性腹膜后纤维化，鉴别诊断是一个挑战，以及IgG4相关疾病（取决于解剖部位）。
Although only small numbers of cases have been reported, and follow-up data are limited, the prognosis appears to be favorable, in contrast to the high rate of metastasis and often poor prognosis of conventional leiomyosarcoma.	虽然只有少数病例被报告，且随访资料有限，但与经典型平滑肌肉瘤的高转移率和预后差相比，炎症性平滑肌肉瘤预后似乎良好。

FIGURE 6. Inflammatory leiomyosarcoma. A, The tumor is composed of relatively uniform, elongated spindle cells with eosinophilic cytoplasm, including scattered atypical forms, admixed with prominent lymphocytes and scattered foam cells. B, Desmin is typically strongly positive.

图6 炎症性平滑肌肉瘤：A、肿瘤由相对一致的细长梭形细胞组成，胞质嗜酸性，包括散在的非典型形态，混有显著的淋巴细胞和散在的泡沫细胞。B、Desmin通常呈强阳性。

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