Cystic meningioma from the falx cerebri.

A study showed the potential impact of 320-row computed tomography (CT) on image-based diagnostic evaluation of cystic meningioma with special attention to the novel techniques of 4-dimensional CT angiography (4D-CTA) and CT whole-brain perfusion (CTP). 4D-CTA showed the arterial supply feeding the tumor and late enhancement of the tumor nodule, similar to that seen in meningioma by conventional angiography. CTP showed that the tumor had a higher cerebral blood flow and cerebral blood volume and a longer mean transit time than adjacent brain tissue. These findings were consistent with meningioma and reinforced the other imaging findings, resulting in the correct preoperative diagnosis. The new techniques available for 320-row CT can potentially be used to improve differential diagnosis and preoperative assessment of cystic tumors with nodules ¹⁾.

A 33-year-old man had suffered from epileptic seizures three times in one month. Physical and neurological examinations on admission were normal. A cystic mass with a small nodule was found on CT in the frontal region. Thin wall was enhanced smoothly and the nodule attached to the falx was enhanced heterogeneously. The mass was considered to be an extra-axial lesion on MRI. The right anterior falcine artery seemed to feed the mass. Bifrontal craniotomy was performed. Cyst was evacuated, and a soft reddish mass was subtotally removed. Cyst fluid was yellowish and protein content was 3.5 g/dl. Histopathological diagnosis was a meningotheliomatous meningioma and tumor cells were present also in the thin cyst wall. At the second operation the mass was completely removed, cyst wall inclusive. When we encounter a cystic mass in the sites of predilection of meningiomas, we have to consider the possibility of a cystic meningioma. If the mass has meningeal vascularization, a correct diagnosis is not difficult. Taking the location of the mass into consideration, an accurate interpretation of CT and MRI findings indicating extra-axial nature of the mass is indispensable ²⁾.

Yamaguchi T, Matsukado Y, Kuratsu J, Uemura S, Kodama T. [Bifrontal cystic falx meningioma. With a reference to the diagnosis and etiological background of cyst formation–case report]. Neurol Med Chir (Tokyo). 1986 Aug;26(8):644-8. Japanese. PubMed PMID: 2433623. ³⁾.