Granulocytic sarcoma with orbit, cauda equina, muscle and peripheral nerve extension but without bone marrow involvement.

We report a very rare case of granulocytic sarcoma (GS) with muscle and peripheral nerve extension but without bone marrow involvement. A 53-year-old woman presented with sciatic pain and diplopia. Magnetic resonance imaging revealed bilateral orbital and cauda equina region tumors. The blood cell count, and bone marrow histology and cytology were normal. The characteristic cerebrospinal fluid (CSF) cytologic picture of CD14+, CD33+, CD4+, CD56+ and positive nonspecific erastase staining suggested the diagnosis of GS. The patient underwent intrathecal and systemic chemotherapy, as if she had acute myeloid leukemia (AML). This case emphasizes the value of CSF cytological examination and the use of an immunocytochemical marker.