Cytologic diagnosis of metastatic embryonal rhabdomyosarcoma in cerebrospinal fluid: A case report.

Rhabdomyosarcoma (RMS) originates from a differentiation block in muscle progenitors. Leptomeningeal metastasis is a rare but devastating complication of RMS which can be caused by dissemination of cancer cells in cerebrospinal fluid (CSF). Here, we present a 4-year-old female with RMS originating from the upper nasal wall. The following histologic and immunohistochemistry analyses combined with molecular testing analysis supported the diagnosis of embryonal rhabdomyosarcoma (ERMS). Results from CSF routine test, magnetic resonance imaging scans and CSF cytology indicated metastatic meningitis, thus confirming the diagnosis of metastatic ERMS in CSF. This is the first report to describe the clinical features of ERMS in CSF.