Spindle-cell rhabdomyosarcoma

KER, keratin, detected by a mixture of GAMS.2, MAK-6, and AEl /AE3 EMA, epithelial membrane antigen VIM, vimentin DES, desmin MSA, muscle-specific actin SMA, smooth muscle (alpha isoform) actin GALD, h-caldesmon S-IOOP, S-100 protein OCN, osteocalcin LM, laminin UL, Ulex europaeus I lectin binding FS, fibrosarcoma SGRMS, spindle cell rhabdomyosarcoma LMS, leiomyosarcoma MPNST, malignant peripheral nerve sheath tumor MSS, monophasic spindle cell synovial sarcoma SCAS, spindle cell angiosarcoma KS, Kaposi s sarcoma FOS, fibroblastic osteosarcoma. 

Leiomyosarcomas are most commonly found in the retroperitoneum in adults. They uncommonly occur in the deep soft tissues of the extremities but may be seen in more superficial sites, particularly in the dermis and subcutis. The differential diagnosis of LMS traditionally includes other sarcomas composed of intersecting spindle-cell fascicles, including fibrosarcoma, MPNST, synovial sarcoma, and spindle cell rhabdomyosarcoma. Additional conditions such as IMT (inflammatory pseudotumor), neurofibroma, and hemangiopericytoma (see Fig. 4.5) are also considerations. 

Cessna MH, Zhou, H, Perkins, SL, et al. Are myogenin and myoDl expression specific for rhabdomyosarcoma A study of 150 cases, with emphasis on spindle cell mimics. Am Surg Pathol 1150 25(9) 1150-1157. 

As in any other organ, immunostains can be of great utility in resolving a variety of spindle cell mesenchymal lesions occurring in the prostate including benign and malignant smooth muscle neoplasms, peripheral nerve sheath tumors, and rhabdomyosarcoma (Table... 

Myoepithelial tumors need to be separated from the rare primary spindle cell sarcoma of the breast, which may include fibrosarcoma (vimentin-positive), leiomyosarcoma, and rhabdomyosarcoma (positive for muscle markers) synovial sarcoma (CK7-I- and CK19-f) malignant nerve sheath tumors (S-lOO-i- and vimen-tin-i-) and malignant fibrous histiocytomas (vimentin-i-). Although each of these tumors may have characteristic... 

DLBCL, solitary fibrous tumor, synovial sarcoma, Kaposiform hemangiosarcoma, neurofibroma, schwannoma, nasopharyngeal carcinoma, dermatofibrosarcoma protuberans, spindle cell lipoma, rhabdomyosarcoma Follicular lymphoma (interfollicular area), Burkitt s lymphoma... 

Embryonal rhabdomyosarcoma (both spindle cell and botryoid types) ... 

Rhabdomyosarcoma is a mesenchymal tumour of grey colour with partially cystic growth. (12) It mainly occurs during childhood. (277) The tumour cells appear small, round or spindle-like, hyperchromatic, occasionally with eosinophilic cytoplasm. (279) They show various stages of differentiation of embryonal skeletal muscle cells. This tumour originates from peribiliary located muscu-... 

FIGURE 17.9 Muscle-specific actin displays cytoplasmic reactivity and highlights spindled and rhabdomyoblastic cells in embryonal rhabdomyosarcoma (immunoperoxidase, x400). 

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