FIGURE 6.

Pathologic features of undefined canine glioma and immunohistochemical features. (A) A roughly equal proportion of oligodendroglioma-like morphology (top) and astrocytoma-like morphology bottom). (B) Two distinct populations of neoplastic cells with small, basophilic cells admixed with mucin separated by islands of less dense neoplastic cells that are more astrocytic in morphology. (C) Regions of basophilic mucin deposition in an undefined canine glioma. (D) Olig2 immunoreactivity in canine oligodendroglioma is characterized by diffuse, intense intranuclear immunoreactivity in virtually all of the neoplastic cells. (E) GFAP immunoreactivity in canine astrocytoma is often patchy, but intense cytoplasmic immunoreactivity is noted in approximately 30% of the neoplastic cells. (F) CNPase immunoreactivity in canine oligodendroglioma is diffusely cytoplasmic and specific for the neoplastic cells.