Cystic meningioma.

Meningiomas are usually solid tumours. Cystic changes in meningiomas are rare. These cysts may occur extratumoural, peritumoural or intratumoural. Diagnostic difficulties arise in cases of cystic meningiomas. Nine cases of cystic meningiomas were operated on in the past 6 years at the department of neurosurgery University of Alexandra. The mean age of patients was 46.2 years. Male to female ratio was 1/2. Less oedema was observed in extratumoural cysts, and more oedema in intratumoural cysts. The fluid contained was dark brown or dirty yellow in intratumoural cysts (type C), xanthochromic in peritumoural cysts surrounded by tumour tissue (Type B), or clear fluid in extratumoural cysts (Type A). Based on these two observations it is proposed that the cyst fluid and peritumoral oedema may represent variable degrees of degeneration or secretion by tumour cells. Pre-operatively diagnostic criteria are presented.