Brain Pathology Case of the Month - August 2019

> Contributed by Sotiris Sotiriou1, Stavroula Pervana2, Stella Chondromatidou3, Ioannis Efstratiou2, Dimitrios Kanakis4
Departments of 1Pathology Department, Faculty of Medicine, Aristotle University of Thessaloniki, 2Pathology Department, and
     3Radiology Department, "Papageorgiou" General Hospital, Thessaloniki, Greece, 4Medical School, University of Nicosia, Nicosia, Cyprus


A 55-year-old male presented to the outpatient clinic with a combination of neurological symptoms for one month, including movement, speech and behavioral symptoms. MRI revealed in the axial T2 sequence a right frontal lobe mass, with surrounding white matter edema and local mass effect, compressing the right lateral ventricle, with a midline shift to the left (Fig. 1a). Furthermore, in the axial and coronal post gadolinium T1 sequences the mass demonstrated ring enhancement (Figs. 1b and 1c). A wide local excision was performed.


Microscopically, the lesion showed a multinodular growth with incomplete fibrous septa and was composed mainly by spindle cells arranged partially in a fascicular pattern of growth within a rich myxoid or collagenous stroma. The areas with the myxoid stroma were hypocellular. The neoplastic cells within these areas had small, atypical and hyperchromatic nuclei (Fig. 1d). On the other hand, within the hypercellular areas the neoplastic cells showed cellular and nuclear pleomorphism and increased mitotic activity, even with atypical mitoses (Fig. 1e). A tendency of the tumor to form perivascular aggregates of neoplastic cells was also observed (Fig. 1f). In addition, a centrally located area of necrosis was present (Fig. 1g). At the tumor margins, large cells with abundant, eosinophilic cytoplasm and centrally located nucleus were noticed (Fig. 1h). These cells were positive for GFAP Fig. 1i) and S-100 protein (Fig. 1j) and obviously represented entrapped non-neoplastic glioneuronal elements. Immunohistochemically, the neoplastic cells were strongly and diffusively positive for vimentin (Fig. 1k) and negative for GFAP, S-100 protein, SMA, desmin, EMA, and cytokeratin AE1/AE3. Immunostaining for p53 showed focal and weak positivity. The Ki-67/MiB-1 proliferation index measured up to 25% (Fig. 1l). What is your diagnosis?


International Society of Neuropathology