炎症性横纹肌母细胞肿瘤4例临床病理分析OA

Objective To investigate the clinicopathological features of inflammatory rhabdomyoblastic tumor(IRMT).Methods Clinicopathological data from 4 patients diagnosed with IRMT were collected.Using immunohis-tochemistry EnVision two-step staining method,morphological and immunohistochemical features were retrospectively analyzed,and relevant literature was reviewed.Results There were 3 males and 1 female,aged at presentation rang-ing from 9 to 30 years.One occurred in the left upper epigastric region and mediastinum,one in the right forearm,and the other two in the left thigh.The clinical symptoms was a painless mass at the affected site.The tumours ranged from 9 to 19 cm in greatest dimensions.Microscopically,3 cases were well circumscribed and surrounded by fibrous pseu-docapsules,1 case showed small foci of infiltration into the surrounding soft tissues.Tumors were composed of epithe-lioid,spindle,and rhabdomyoblast-like cells.All tumors displayed an inflammatory infiltrate composed of histiocytes and lymphocytes.Tumor cells revealed 0-2 mitotic figures/10 HPF.Necrosis was absent.Tumor cells expressed des-min,SMA,limited expression of MyoD1 and Myogenin,and H-caldesmon was positive in one case.CD163 and CD68 were expressed in histiocytes.Ki67 proliferation index was 5%-20%.Follow-up informations were available for all four cases,with a duration of 10 to 24 months,and all cases had no recurrence and metastasis.Conclusion IRMT is a newly recognized skeletal muscle tumors with uncertain malignant potential.It is characterized by variable cellular pleomorphism,low mitotic activity and abundant lymphohistiocytic inflammation,with potential for progression to in-vasive sarcoma.