Intranasal pericytic tumors (glomus tumor and sinonasal hemangiopericytoma-like tumor): report of two cases with review of the literature.

An intranasal glomus tumor and a sinonasal hemangiopericytoma-like tumor are reported. Both patients were elderly women suffering from nasal bleeding, and presented with a polypoid mass arising in the nasal septum. Microscopically, the glomus tumor displayed a proliferation of uniform rounded or cuboidal epithelioid cells arranged in sheets and interrupted by a rich vasculature with a characteristic configuration mimicking the normal glomus bodies, while the sinonasal hemangiopericytoma-like tumor featured a perivascular proliferation of spindle- to oval-shaped cells that were arranged in short fascicles. Both tumors shared immunohistochemical features supporting their myoid differentiation by the expression of vimentin, alpha-smooth muscle actin and muscle-specific actin, albeit with no immunoreaction to desmin. Both the intranasal glomus tumor and sinonasal hemangiopericytoma-like tumor are characterized by a perivascular growth pattern and myoid differentiation, having a close relation to the 'perivascular myomas', which was recently designated.