الفهرس 
Incidence of soft tissue tumorsOnly 14 pages are availabe for public view
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Abstract
Soft-tissue tumors are rare neoplasms. They constitute less than 1% of all cancers. Due to their rarity as well as the wide variation and frequent overlap in their histopathological features, accurate diagnosis of soft-tissue tumors is a constant challenge to pathologists. Immunohistochemistry plays a key role in the diagnosis of spindle cell soft tissue tumors because of their variety with several lines of differentiation, and the frequent difficulty of diagnosis with numerous pseudosarcomatous benign lesions and non-mesenchymal malignant tumors. Interpretation of IHC results is dependent on proper technique, strict use and interpretation of well-characterized positive and negative controls, and detailed knowledge about the performance of reagents. This study was performed on 70 cases of spindle cell soft tissue lesions in order to study their histopathologic features and immunohistochemical criteria. 81.4% of cases were diagnosed as spindle cell sarcoma and 18.6% of cases were lesions mimicking spindle cell sarcoma. Regarding sarcoma cases in this study, the peak incidence was in the 4th and 5th decades. There was slight male predominance with male to female ratio 1.2:1. Extremities were the most frequently affected site especially the lower limb. The most common type of soft tissue spindle cell sarcoma was MPNST representing 31.6% of cases. All these tumors were positive for S100. Rhabdomyosarcoma represented 19.3% of cases and all cases were desmin positive. Synovial sarcoma represented 17.5% of cases and all of them were focally positive for CK AE1/AE3. leiomyosarcoma represented 10.5% of the cases. All cases expressed SMA and half of the cases expressed desmin. Pleomorphic MFH represented 10.5% of the cases and this diagnosis was reserved for pleomorphic sarcomas with no specific line of differentiation. Liposarcoma represented 5.3% of cases and the IHC profile was not specific and the diagnosis was made by excluding other tumor types. Fibrosarcoma represented 5.3% of the cases and all cases revealed positivity only for vimentin. As regard lesions mimicking spindle cell sarcoma, spindle cell carcinoma represented 30.8% of cases. These tumors were cutaneous and showed positivity for CK AE1/AE3. spindle cell melanoma represented 30.8% of cases and they were diffusely positive for S100 and HMB45. cellular schwannoma represented 23% of cases and all cases were diffusely positive for S100. nodular fasciitis represented 15.4% of cases and showed SMA positivity and desmin negativity.