Xu Pei, Shen Pingping, Jin Yangli, Wang Li, Wu Weiwei
Department of Burns, Ningbo Huamei Hospital, University of Chinese Academy of Science (Ningbo No. 2 Hospital) Ningbo, China.
Department of Gastroenterology, Yinzhou Second Hospital Ningbo, China.
Int J Clin Exp Pathol. 2019 May 1;12(5):1738-1744. eCollection 2019.
Inflammatory myofibroblastic tumor (IMT) is a neoplasm composed of spindled neoplastic myofibroblasts admixed with reactive lymphoplasmacytic cells, plasma cells, and/or eosinophils, which has an intermediate biological behavior. An IMT variant with plump round epithelioid or histiocytoid tumor cells, recognized as epithelioid inflammatory myofibroblastic sarcoma (EIMS), has a more clinically aggressive progression. To the best of our knowledge, only about 40 cases of EIMS have previously been reported in limited literature. Here, we report here a case of unusual EIMS with a relative indolent clinical behavior. We reviewed the literature for 18 similar cases. The patients present with a highly aggressive inflammatory myofibroblastic tumor characterized by round or epithelioid morphology, prominent neutrophilic infiltrate, and positive staining of ALK with RANBP2-ALK gene fusion or RANBP1-ALK gene fusion, or EML4-ALK gene fusion. Our case is the first case of primary stomach EIMS. Moreover, the mechanisms of the rare entity have not been widely recognized and require further study. Early accurate diagnosis and complete resection of this tumor is necessary. Some researchers suggest expression of PD-L1 may provide new strategies for ALK-targeted therapy.
炎性肌纤维母细胞瘤（IMT）是一种由梭形肿瘤性肌成纤维细胞与反应性淋巴细胞、浆细胞和/或嗜酸性粒细胞混合组成的肿瘤，具有中间型生物学行为。一种具有丰满圆形上皮样或组织细胞样肿瘤细胞的IMT变异型，被认为是上皮样炎性肌纤维母细胞肉瘤（EIMS），其临床进展更具侵袭性。据我们所知，此前在有限的文献中仅报道了约40例EIMS。在此，我们报告一例具有相对惰性临床行为的罕见EIMS病例。我们回顾了文献中的18例类似病例。这些患者表现为一种高度侵袭性的炎性肌纤维母细胞瘤，其特征为圆形或上皮样形态、显著的中性粒细胞浸润，以及ALK染色阳性伴RANBP2-ALK基因融合或RANBP1-ALK基因融合，或EML4-ALK基因融合。我们的病例是原发性胃EIMS的首例。此外，这种罕见实体的发病机制尚未得到广泛认识，需要进一步研究。早期准确诊断并完整切除该肿瘤是必要的。一些研究人员认为，PD-L1的表达可能为ALK靶向治疗提供新策略。
