1999 年 4 巻 1 号 p. 31-34
A case of atypical meningioma, which invaded the extracranial tissue and resulted in the broad swelling of the right temporomandibular region, is reported. A 53-year-old male had a lesion with a combination of osteolytic and osteoplastic reactions in the temporal bone, which was clinically diagnosed as malignant neoplasm or osteomyelitis. The biopsy specimen revealed that invading nests show biphasic immunoreactivity of vimentin and EMA, micronecrosis and over-expression of p53. However, mitosis and Ki-67 labelling indices of tumor cells were estimated to be less than 2/10 HPFs and 5.8% respectively, so that this case was diagnosed as atypical meningioma.