Myofibroblastic sarcoma in meningioma: a new variant of "metaplastic" meningioma.

The authors describe a mixed malignant dural tumor composed of meningioma and myofibroblastic sarcoma (MFS). The meningioma component displayed epithelial membrane immunoreactivity and interdigitating cellular processes with desmosomal junctions on electron microscopy. MFS cells were immunoreactive for smooth muscle actin and vimentin, and focally for factor XIIIa, CD31, CD34, and Ulex europeus lectin receptors. Electron microscopy showed collections of intermediate filaments, stress fibers, subsarcolemmal densities of microfilaments, occasional fibronexus fibrils, few pinocytic vesicles, and discontinuous external lamina. After gross total removal, the tumor recurred 1 year later as aggressive MFS only. Development of MFS in continuity with meningioma suggests induction of MFS by meningioma or a divergent differentiation of precursor of the neoplastic arachnoid cell.

Myofibroblastic sarcomas: a clinicopathological study of 20 cases.

BACKGROUND: Myofibroblastic sarcoma was used to be a controversial neoplasm. This study investigated the clinicopathological features of 20 cases of myofibroblastic sarcoma arising in different locations. METHODS: The paraffin-embedded tissue samples from 20 cases of patients with myofibroblastic sarcoma were stained immunohistochemically, and 5 cases examined by electron microscopy. Student's t test was used to analyze the difference of Ki-67 labeling index between grade 1 and grade 2 myofibroblastic sarcomas. RESULTS: Histologically, the tumors were composed of slender spindle cells with eosinophilic cytoplasm, and fusiform, tapering, wavy, or plump ovoid; vesicular nuclei and a small central eosinophilic nucleoli. Immunohistochemically, the tumor cells expressed smooth muscle actin (18/20), muscle specific actin (16/20), fibronectin (20/20) and desmin (2/20). Ultrastructurally, the tumor cells revealed abundant rough endoplasmic reticulum and longitudinally arranged fine filaments with focal densities in the cytoplasm. A clinical follow-up of 19 patients showed that 2 cases experienced local recurrence and distant metastasis 6 months to 4 years after the initial operation. Nine cases recurred locally 17 to 46 months after the initial excision, and 9 cases were alive with no evidence of disease. CONCLUSIONS: Myofibroblastic sarcomas, which exhibit diverse histological appearance, can easily be misdiagnosed as benign tumors. Myofibroblastic sarcomas are local destructive lesions with frequent recurrence, and may metastase distantly.

Myofibroblastic sarcoma of the nasal cavity and paranasal sinus: a clinicopathologic study of 6 cases and review of the literature.

OBJECTIVE: We describe the clinicopathologic features of 6 cases of myofibroblastic sarcoma (MS) occurring in the nasal cavity and paranasal sinus. STUDY DESIGN: The paraffin-embedded tissues of 6 cases of MS were stained immunohistochemically and examined by electron microscopy. RESULTS: Clinically, a painless enlarging mass was the most common symptom, followed by the nasal obstruction, epistaxis, copious rhinorrhea, and proptosis. Histologically, the tumors showed a diffusely infiltrative growth pattern and consisted mainly of spindle cells with abundant eosinophilic cytoplasm. The hypocellular myxoid areas and the hypercellular fibrous areas were identified. Immunohistochemically, all 6 tumors were positive for vimentin, alpha-smooth muscle actin, calponin, and fibronectin. Ultrastructural examination in 3 cases showed characteristic features of myofibroblast. Follow-up in 6 patients revealed high local recurrence rate (6 out of 6). CONCLUSION: Myofibroblastic sarcoma of the nasal cavity and paranasal sinus exhibit diverse histologic appearances and a strong aggressive behavior.

Myofibrosarcoma of the bone: a clinicopathologic study.

Myofibroblastic tumors are fairly recently established soft tissue neoplasms. Although most of them appear to be benign, myofibrosarcoma of the soft tissue, seemingly their malignant counterpart, have been reported. We describe the clinicopathologic and radiologic features of four cases of myofibrosarcoma arising from the bone. All but one of the patients were women ranging in age from 60 to 71 years. Two tumors occurred in the metaphyses of distal femurs and the others arose in the iliac bones. On radiologic examination all tumors exhibited well-demarcated lytic destructive lesions without periosteal reaction. Two tumors were localized in the bone, whereas the other two extended into surrounding soft tissues. Histologically, all tumors were composed principally of a mixture of a cell-rich fascicular area and a hypocellular fibrous area. In the former area tumor cells had rather eosinophilic spindle-shaped wavy cytoplasm and were arranged in interlacing fascicles and small storiform patterns with variable numbers of inflammatory cells. Tumors occasionally showed prominent pleomorphism, and large cells with hyperchromatic nuclei were seen. In contrast, hypocellular areas had various features, including collagenous, hyalinous scar-like and rarely keloid-like areas. Focal coagulation necroses were present in all but one tumor. Immunohistochemically, the tumors were positive for vimentin, muscle actin (HHF35), alpha-smooth muscle actin, calponin, and desmin, whereas all of them were negative for high molecular weight caldesmon. On follow-up there was one fatal case with distant metastases, whereas the clinical courses of other cases after wide resection were excellent. Myofibrosarcoma of the bone has distinctive histopathologic features, which should be distinguished from those of other bone tumors with myoid differentiation.

[Malignant glial tumor with skeletal muscle differentiation. Description of a case]. / Tumore gliale maligno con differenziazione muscolare scheletrica. Descrizione di un caso.

A case of CNS gliomyosarcoma, in a 71-year-old female with skeletal muscle differentiation is presented. The tumor was composed by two cell types: one showed features typical of glial cells, the other was constituted by elements having immunohistochemical positivity with desmin, sarcomeric actin, myoglobin and myogenin antisera. It is postulated an origin from a cell capable of dual differentiation.

Expression of beta 2-microglobulin by human benign and malignant mesenchymal and neurogenic tumours.

Human myosarcomas, liposarcomas, meningosarcomas, glioblastomas and malignant schwannomas, their benign counterparts and normal cells from which these tumours derive, were examined for the expression of beta 2-microglobulin (beta 2m). Formalin fixed specimens from these tumours were studied by light microscopy employing the immunoperoxidase method with the use of antibodies directed towards beta 2m. The malignant tumours showed a broad spectrum from unstained to strongly stained tumours, most pronounced among myosarcomas. In addition, most stained tumours displayed a mosaic staining pattern in that unstained areas alternated with stained. There was a tendency towards increased staining for beta 2m in malignant compared to normal cells; this was also observed in the benign tumours although to a lesser degree. The results differ from most earlier studies, mainly of carcinomas which have shown a tendency towards down-regulation of MHC I molecules on the tumour cells. The results are discussed in relation to concepts of immune surveillance of tumours.