Multiple intracranial subarachnoid osteomas

OBJECTIVE AND IMPORTANCE: Intracranial osteomas, which have no connections with the dura or the skull, are very rare. Here we report one case of multiple intracranial subarachnoid osteomas. CLINICAL DESCRIPTION: A 24-year-old gentleman, who had no previous history of systemic disease, meningitis or head injury, presented with a 6-month history of non-specific intermittent headache over the whole head. Neuro-imaging showed multiple ossified lesions in the right frontal area, which were found to compress the underlying cerebral hemisphere. The patient underwent a right frontal craniotomy. The masses were dissected from the depressed brain along the intact pial planes, however, all of the white bone-hard masses tightly adhered to the superficial cortical veins. The masses were removed and the cortical veins were sacrificed. The patient had headaches and was nauseous for three days after the surgery due to venous congestion; however, the patient was neurologically intact on discharge. Pathological diagnosis was osteoma. CONCLUSION: To our knowledge, this is the first report of multiple intracranial subarachnoid osteomas. Surgical findings strongly support the hypothesis of the origin of the tumour that the primitive mesenchymal cells from the connective tissue might have migrated into the subarachnoid space accompanying the intracerebral blood vessels.