Figure 3
From: Primary mediastinal atypical meningioma: Report of a case and literature review
Numerous typical whorl formations (A) and small cells with a high nuclear/cytoplasmic ratio (B) were observed in the tumor. Spontaneous necrosis was occasionally seen (C). The tumor was partially involved in the adjacent pulmonary parenchyma (D). There were some mitotic figures, and the Ki-67/MIB-1 labeling index was approximately 7% in relatively higher positive-rate fields (E). Marked immunoreactivity for epithelial membrane antigen (EMA) was seen (F).