Lobulated with loose fascicular pattern
Spindle cells with pale amphophilic cytoplasm and long bipolar processes
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Clefting artifact
IHC: claudin-1, CD34, epithelial membrane antigen, GLUT1
Circumscribed; loose fascicular-whorled pattern
Spindle cells with pale amphophilic cytoplasm and long bipolar processes
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Central cystic change
IHC: GLUT1, claudin-1
Lobulated with loose fascicular pattern
Spindle cells with pale amphophilic cytoplasm and long bipolar processes
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Intervening bands and lobules of collagen
IHC: CD34, epithelial membrane antigen, GLUT1, claudin-1
Spindle cells with fascicular-storiform pattern
Pale amphophilic cytoplasm and long bipolar processes
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Intervening collagen bands
IHC: CD34, claudin-1, GLUT1
Remote history of perineurioma
Heterogeneous with areas of hyper- and hypo- cellularity
Ovoid cells arranged in sheets with scant amphophilic cytoplasm and indistinct cell borders; ovoid nuclei with mild atypia; mitotic activity
Spindle-stellate cells with reticular pattern; eosinophilic cytoplasm; ovoid nuclei with mild atypia; inconspicuous mitotic activity
Spindle cell arranged in fascicles with pale amphophilic cytoplasm and long bipolar processes; ovoid nuclei with mild atypia; inconspicuous mitotic activity; abundant intervening collagen
Necrosis
IHC: CD34