Brain Pathology Case of the Month - December 2006  FINAL
DIAGNOSIS: Myxoid meningioma   The metaplastic variants of
meningioma are an interesting subgroup that highlight the broad
histological repertoire of these neoplasms (8). Of these
variants, myxoid meningioma poses a particularly difficult
diagnostic challenge. These lesions do not display the usual
histological features of more typical meningiomas and have
abundant mucoid stroma that mimics other myxoid tumors.
Currently, the diagnosis of myxoid meningioma is contingent on:
1) recognition that the tumor arises from the leptomeninges, 2)
discovery of obscure meningioma histology, 3) extensive Alcian
blue staining, 4) identification of tight junctions and basal
lamina, and 5) exclusion of other myxoid tumors (2-5, 7).
Notable among the histologic features of myxoid meningiomas is
that they demonstrate little or no immunoreactivity to
recommended dilutions of EMA. In addition, immunostaining for
other cytokeratins, smooth muscle actin, muscle-specific acti