MENINGEAL RHABDOMYOSARCOMA - REPORT OF A CASE WITH CYTOLOGIC, IMMUNOHISTOLOGIC AND ULTRASTRUCTURAL STUDIES

Primary rhabdomyosarcoma of the meninges, a very rare brain tumor, is reported. Cytologic findings by squash preparation were useful as an a djunct to frozen section diagnosis during surgery. The cytologic featu res of rhabdomyosarcoma without cross-striation have some similarities to those of gemistocytic astrocytomas and anaplastic meningiomas, but the cytoplasmic filaments of rhabdomyosarcoma are different from thos e of gemistocytic astrocytoma and anaplastic meningioma. Histologicall y the tumor runs embryonal rhabdomyosarcoma with a partially botryoid pattern. The tumour cells have no cross-striations but react positivel y to antimyoglobin serum oil immunoperoxidase staining. In this case, intracytoplasmic filaments resembling poorly formed myofibrils were fo und on electron microscopic study. The histologic and immunohistologic findings suggest that this rare mesenchymal malignancy might arise fr om primitive totipotential cells.