Melanocytic schwannoma: the cytologic aspect in fine-needle aspiration cytology (FNAC): report of a case located in the spinal cord.

We describe a case of intramedullary melanocytic schwannoma (MS) studied by means of fine-needle aspiration cytology (FNAC). The main cytologic features were (1) large three-dimensional clusters overshadowed by heavy pigment deposits which tested positive for Fontana Masson (and bleached with potassium permanganate), HMB-45, Vimentin, and S-100 protein; (2) loose syncytial monolayered sheets with very little pigment deposit; and (3) isolated spindle cells with polarized nucleus and tapered, thin cytoplasmic ends. Both the cytologic features and the immunophenotypic profile were nonspecific and on their own were insufficient to allow the diagnosis of MS to be reached. Clinical data and the magnetic resonance image (MRI) in conjunction with the cytologic findings did suggest the diagnosis of intramedullary MS.