A 59-year-old man presented with a 6-month history of headaches. Magnetic resonance imaging of the brain showed an enhancing extraaxial mass in the right frontal area and marked midline shift (Figure 1A). Histologic features of the tumor (Figure 2A and B) were consistent with an atypical meningioma (World Health Organization grade II). The Ki-67 proliferative index was 8.9% with a mitotic index of 12.6 mitoses/10 hpf. CD44 immunostaining was slightly positive in only a few regions. Recurrence a year later showed histologic features of an anaplastic meningioma (World Health Organization grade III) with a Ki-67 proliferative index of 32%, mitotic index of 18 mitoses/10 hpf, and more intense and diffuse immunoreactivity for CD44. A technetium Tc 99m–methylene diphosphate bone scan (Figure 1B) was performed 2 months after resection of the recurrence showing multiple lytic lesions in the ribs, sternum, and L4 vertebra. A large soft tissue mass in the right gluteus maximus muscle was also seen (Figure 1C), with the biopsy specimen showing spindle and epithelioid-appearing cells that were morphologically identical to the patient's anaplastic meningioma (Figure 2C). Epithelial membrane antigen (Figure 2D) and CD44 immunostains were positive.