Benign Meningioma With Rare Radiological and Behavioral Features.

BACKGROUND

Meningiomas are usually dura-based primary nonmalignant neoplasms of the central nervous system. It is extremely rare that a meningioma is located at the convexity of the brain, but shows no dura attachment and causes osteolysis of the skull.

CASE PRESENTATION: A 57-year-old woman presented with an incidentally discovered scalp lump on the head. Neurological deficits were not found. Radiological examination revealed a localized osteolytic lesion in the right parietal bone, which was initially diagnosed as a bone tumor and was surgically resected. At surgery, a tumor mass was found located at the brain convexity without dura attachment. It was tightly attached to the brain parenchyma and had no distinct boundary from the brain. The mass was rather small, but resulted in significant osteolysis of the skull and destruction of the dura. Simpson grade I resection of the tumor was performed. Histological and immunohistochemical results indicated a meningothelial meningioma.

CONCLUSIONS

Both preoperative and intraoperative diagnoses are difficult for this case. Knowledge of this case is crucial for clinicians to be aware of this entity because it can be easily confused with bone tumors. Further research on the relationship between meningioma and bone metabolism is required to investigate the mechanism of osteolysis.