Embryonal rhabdomyosarcoma in ascitic fluid. Immunocytochemical and DNA flow cytometric study.

We report the case of an 18-year-old woman who had a small-cell malignant neoplasm of the left paranasal sinuses and who, 18 months later, developed malignant ascites. Immunoperoxidase stains of the ascitic fluid cells and, subsequently, the original tumor, identified it as embryonal rhabdomyosarcoma. Flow cytometric DNA analysis of the ascitic fluid demonstrated an aneuploid cell population that was also present in the paraffin-embedded tissue on which the original diagnosis had been made.