Though currently classified as a variant of nerve sheath myxoma or neurothekeoma, this tumor often has spindle cells in a fascicular pattern and may contain cellular areas with little mucinous material. Mucinous lobules, if present, often have infiltrating characteristics.  Cytologic atypia, mitoses, neurotropic foci and giant cells may be present. There may be foci resembling plexiform fibrohistiocytic tumors. Cellular neurothekeomas are usually S-100 negative.

 Examples having little mucinous material and conspicuous fascicular patterns may be confused with spindle cell nevi and desmoplastic melanomas. Fortunately, spindle cell nevi and desmoplastic melanomas are usually S-100 positive.

	Scan power view showing fascicular patterns and patterns that are more solid.
	Low power view of fascicular pattern.
	High power view of above. Note the mucinous matrix.
	Low power view of a relatively solid area.
	High power view of above. Note the degree of cellularity.
	Low power view of a mucinous area containing very few cells. The mucinous foci  infiltrate between reticular dermis collagen bundles as well as having a pushing border. Foci such as this are characteristic of nerve sheath myxomas or mature neurothekomas.
	High power view of a fascicle without appreciable mucinous stroma.
	High power showing perineural involvement. Arrow points to the nerve.

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