A note on immunohistochemical staining for sarcomeric actin in rhabdomyosarcomas and other round cell tumours

Primary Renal Rhabdomyosarcoma in an Adolescent With Tumor Thrombosis in the Inferior Vena Cava and Right Atrium: A Case Report and Review of the Literature

Although the second peak of the age distribution of rhabdomyosarcoma (RMS) is at adolescence, renal RMS is extremely rare at this age group. This tumor is indistinguishable from other renal tumors based on clinical and imaging findings, and the diagnosis relies on histology and immunohistochemical staining. We report a unique case of adolescent renal RMS associated with tumor thrombus extending into the inferior vena cava (IVC) and right atrium.An 18-year-old female adolescent presented with shortness of breath and palpitations, associated with right flank discomfort, and hematuria. A pleomorphic-type renal RMS with Budd-Chiari syndrome and arrhythmia induced by IVC and RA thrombosis was diagnosed. Despite complete tumor resection, the patient developed multiple lung metastases a month after surgery. Chemotherapy was recommended, but the patient declined. She died within a year of the initial operation.Adolescent renal RMS is rare and associated with poor outcome. Early aggressive multimodal therapy seems to be appropriate, in particular, in the presence of tumor thrombosis.

The expression pattern of contractile and intermediate filament proteins in developing skeletal muscle and rhabdomyosarcoma of childhood: diagnostic and prognostic utility

In order to investigate whether rhabdomyosarcoma (RMS) can be related to equivalent stages of skeletal muscle development, muscle tissue of 21 human foetuses and 112 primary RMSs were characterized immunohistochemically using antibodies directed against vimentin, desmin, muscle-specific actin (HHF35), sarcomeric actin (sr-actin), smooth muscle actin (sm-actin), and troponin-T. During fetal skeletal muscle development, all myotubes/fibres of the first and second generations expressed desmin, HHF35, and sr-actin. Vimentin was almost exclusively present in immature primary and secondary myotubes/fibres. Troponin-T was expressed in immature myotubes/fibres of the first and second generations as well as mature fibres of the second generation. Sm-actin was never expressed. Vimentin was expressed in 96 per cent of primary and 98 per cent of relapsed RMS; HHF35 in 96 and 98 per cent, respectively; desmin in 95 and 100 per cent; troponin-T in 82 and 75 per cent; sr-actin in 71 and 86 per cent; and sm-actin in 13 and 17 per cent. The proportion of RMS cells reacting with vimentin, HHF35, and desmin was consistently higher than those expressing sr-actin and troponin-T. Neither the shape nor size of neoplastic RMS cells nor the histopathological types were related to the expression pattern of the investigated markers. RMS with aberrant expression of two or more markers predicted a worse prognosis than RMS in which at most one marker was aberrantly expressed (25 per cent and 54 per cent 10-year survival, P = 0.01). These results demonstrate that HHF35, desmin, sr-actin, and troponin-T have the potential to confirm the commitment of the tumours to the myogenic pathway which supports the diagnosis of RMS. However, it was impossible to relate RMS to equivalent stages of skeletal muscle development. Aberrant marker expression by RMS cells correlated significantly with patients' survival.