Rapidly enlarging chordoid meningioma with abundant mucin production.

This 77-year-old woman with a rapidly enlarging chordoid meningioma first noticed a growing, non-pulsatile, nonpainful soft mass in the left temporal region after a head trauma 2 years earlier. Neuroimaging showed a homogeneously enhanced osteolytic mass lesion in the left temporal bone. Surgery revealed an extradural tumor without significant adhesions. Histopathologically it was a meningioma with features reminiscent of chordoma. Most of the tumor cells contained mucin-rich chordoid elements. Immunohistochemically, the lesion was positive for vimentin and epithelial membranous antigen; it was negative for cytokeratin and S-100 protein. Based on these findings a diagnosis of chordoid meningioma was made. We posit that the rapid enlargement of the tumor over a relatively short period was attributable to its high mucin-producing activity.