Intraosseous meningioma mimicking osteosarcoma in an adolescent: a case report.

Intaosseous meningiomas (IM) are the one of the less frequent benign tumors of the skull. The etiology of IM has not been cleared yet. The frontoparietal and orbital regions are the most common locations for IM. The average age for IM diagnosis is 50.5. A 16-year-old girl with a right frontoparietal mass was referred to our outpatient clinic. Cranial CT revealed a mass lesion which resulted in expansion in the right parietal and posterior frontal bone, having lytic and sclerotic regions inside with accompanying irregular cortex in inner and outer tables of the calvarium. Prediagnosis was osteosarcoma according to the imaging studies and after the performed biopsy and consecutive surgery, the lesion was diagnosed as IM. Though CT with bone windows is often useful, it is not always diagnostic. Biopsy plays an important role in calvarial vault lesions for planning the treatment. In our case, malignant criteria in radiology did not match the benign histology revealed. Radiological preoperative misdiagnosis of meningioma is possible.