Abstract：
Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare variant of inflammatory myofibroblastic tumors located mostly in the intra-abdominal region. Herein, we present a case of a 32-year-old male with a lobulated growth in the right maxilla. Radiology revealed a solitary osteolytic lesion with an irregular margin, causing buccal and palatal cortex erosion. Histopathology revealed a tumor composed of spindle-shaped fascicles that blend into sheets of round to ovoid-shaped epithelioid cells, areas of myxoid changes, and necrosis. Tumor cells showed a moderate amount of eosinophilic cytoplasm, large vesicular nuclei with coarse chromatin, nuclear pleomorphism, and increased mitoses. Tumor cells were immunopositive for ALK-1, focal positivity for smooth muscle actin, panCK, epithelial membrane antigen, and immunonegativity for CD 30, desmin, CD34, and STAT6. P53 showed a wild-type staining pattern, and INI-1 expression was retained. The Ki-67 proliferative index was 22%. To the best of our knowledge, this is the first case of EIMS occurring in the maxilla.
摘要：
上皮样炎性肌纤维母细胞肉瘤（EIMS）是炎性肌纤维母细胞瘤的一种罕见变体，主要位于腹内区域。在这里，我们介绍了一例32岁的男性，其右上颌骨有叶生长。放射学显示孤立性溶骨性病变，边缘不规则，导致颊和腭皮质侵蚀。组织病理学显示肿瘤由纺锤形的束组成，混合成圆形到卵形的上皮样细胞，粘液样变化的区域，和坏死。肿瘤细胞显示中等数量的嗜酸性细胞浆，带有粗染色质的大泡状核，核多态性，和增加有丝分裂。肿瘤细胞ALK-1免疫阳性，平滑肌肌动蛋白局灶性阳性，PANCK,上皮膜抗原，和CD30的免疫阴性，CD34和STAT6。P53呈野生型染色模式,INI-1表达得以保留。Ki-67增殖指数为22%。据我们所知,这是第一例发生在上颌骨的电刺激综合征。
