Sarcomas leiomyosarcoma

Desmin is a specific marker for myogenic differentiation among soft tissue tumors, seen in almost all rhabdomyo-sarcomas/leiomyosarcomas, rhabdomyomas/leiomyomas. 

In addition to epithelial neoplasms, a number of sarcomas, CNS tumors, small round cell tumors, and a few germ cell tumors may be positive with EMA. These tumors include malignant nerve sheath tumors, synovial sarcoma, leiomyosarcoma, malignant fibrous histiocytoma, epithelioid sarcoma, and chordoma. With the exception of the last two tumors mentioned, EMA immunostaining is focal. 

Noncarcinomatous lesions Plasma cell tumors, L H cells of Hodgkin lymphoma, few cells of non-Hodgkin lymphoma, anaplastic large cell lymphoma, malignant peripheral nerve sheath tumors, synovial sarcoma, leiomyosarcoma... 

In reference to still other mesenchymal neoplasms, experience since the 1990s has shown that under some circumstances, selected tumors that are typically devoid of keratins may synthesize those IFPs in an aberrant fashion (Table 4.2). Indeed, at this point, virtually all sarcoma morphotypes have been reported to show this potential. Nevertheless, we would like to emphasize that aberrant keratin reactivity is most common in a narrow spectrum of malignant mesenchymal neoplasms that are studied under usual diagnostic conditions, principally leiomyosarcoma (LMS), malignant peripheral... 

Fetal fibroblasts myometrium vascular smooth muscle fetal myocardium vascular endothelial cells selected reticulum cells of lymphatic organs some CD30+ lymphoid cells (rarely) selected leiomyosarcomas, epithelioid hemangioendotheliomas, epithelioid angiosarcomas, primitive neuroectodermal tumors and Ewing s sarcomas, malignant peripheral nerve sheath tumors, and clear cell sarcomas... 

Myometrium fetal myocardium selected neoplastic myeloid cells some leiomyosarcomas rare primitive neuroectodermal tumors and Ewing s sarcomas... 

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. 

ELMS, epithelioid leiomyosarcoma ASPS, alveolar soft part sarcoma HMFH, histiocytic malignant fibrous histiocytoma EOS, epithelioid osteosarcoma. 

Keratins are regularly found in synovial sarcoma, chordoma, parachordoma, epithelioid sarcoma, and adamantinoma. They are seen less commonly in leiomyosarcoma, malignant peripheral nerve sheath tumors, epithelioid angiosarcoma, and polyphenotypic tumors such as PNET. 

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. 

KER, keratin (mixture of monoclonal antibodies) EMA, epithelial membrane antigen VIM, vimentin CALRET, calretinin DES, desmin MSA, muscle-specific actin AFP, alpha fetoprotein SYN, synaptophysin CCA, chromogranin A MESOTH, mesothelioma SCYST, spindle cell yolk sac tumor LMS, leiomyosarcoma SPCCA, spindle cell carcinoma (either primary or metastatic) SYNSC, synovial sarcoma SPCNC, spindle cell neuroendocrine carcinoma FS, fibrosarcoma MFH, malignant fibrous histiocytoma. 

Immunohistochemically, leiomyosarcomas commonly express vimentin, actin, and desmin. Cytokeratin expression is observed in about one quarter of cases. In addition, some leiomyosarcomas have been reported to express progesterone receptor, similar to STUMPs and stromal sarcomas (Table Leiomyosarcomas... 

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... 

Given the vast number of cell types present in the esophagus, a variety of tumors can arise. Spindle cell carcinoma, small-cell carcinoma, leiomyosarcoma, Kaposi s sarcoma, and malignant melanoma comprise rare malignant esophageal tumors. The vast majority of primary malignant tumors of the esophagus, however, include squamous cell carcinoma and adenocarcinomas. 

Few mesenchymal tumors including desmoplastic small round cell tumor, leiomyosarcoma and monophasic synovial sarcoma. 

Wilms tumor protein-1 (WT-1) Nephroblastoma, mesothelioma, metanephric adenoma, ovarian serous carcinoma AML, desmoplastic small round cell tumor, endometrial stromal sarcoma, uterine leiomyosarcoma, granulosa cell tumor, thecoma, rhabdoid tumor Kidney, mesothelial cells, granulosa cells, Sertoli cells, fallopian tube endometrial stroma, spleen... 

The ambiguous histological differentiation and the controversial immunophenotype of synovial sarcoma make the microscopic diagnosis difficult, especially when the tumor occurs in atypical locations or when the tumor reveals a non-specific immunohistochemical phenotype, which may resemble the immunophenotypic profile of other malignancies such as different types of sarcoma (solitary fibrous tumor, malignant peripheral nerve sheet tumor, fibrosarcoma, epithelioid sarcoma or leiomyosarcoma), metaplastic carcinoma and mesothelioma. Since synovial sarcoma reveals a different clinical behavior than the other mentioned tumors, it is important to discriminate it from these malignancies and additional methods that are more specific may be necessary to confirm the diagnosis. 

Lymphoma, metastases, sarcoma (liposarcoma, fibrosarcoma, leiomyosarcoma, rhabdomyosarcoma, lymphosarcoma)... 

Vascular tmnors Angiosarcoma Hemangiosarcoma Epithelioid hemangioendothelioma Leiomyosarcoma Fibrosarcoma Embryonal sarcoma Fibrous histiocytoma Lymphoma (Hodgkin s disease) Lymphoma (non-Hodgkin s disease)... 

With the exception of angiosarcomas, sarcomas of the liver are rare tumors. Other sarcomas of the liver include leiomyosarcoma, malignant fibrous histiocy-... 

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