Nerve sheath myxoma of the tongue in a child.

Nerve sheath myxoma (NSM) is a benign peripheral nervous system tumour that rarely occurs in the oral cavity. Among 17 cases of oral NSM described in the literature (average patient age 33 years), only two, including the present case, have been reported in children. The present case occurring in an 8-year-old boy was therefore extremely rare. Histopathologically, the tumour was found as multinodules under the mucosal epithelium, and was composed of spindle- or stellate-shaped cells with a myxoid background that stained with alcian blue and toluidine blue. Immunohistochemically, the tumour cells were strongly positive for S-100 beta protein and neuron-specific enolase. These results suggested that the tumour originated from Schwann cells.