Parietal convexity meningioma
Meningiomas presented preferred intracranial distribution, which may reflect potential biological natures.
Higher Ki67-index at the left frontal and bilateral parietal convexity meningioma and right parasellar/cavernous sinus 1)
Clinical features
Cataleptic attacks or atonic seizures have been described in cases of frontal lesions due to meningiomas. Five new cases are reported: 3 frontal and 2 parietal meningiomas. In 3 of the cases, the attacks started before the removal of the tumors. A consecutive case material of 66 intracranial meningiomas verified neurosurgically was re-examined. Only 2 patients had cataleptic attacks and were included among the 5 cases reported. Both had a parietal convexity meningioma. Although most cases of cataleptic attacks after the age of 50 probably are of vascular origin, the possibility of a frontal or parietal meningioma should be considered. It is suggested that the cataleptic attacks in these cases are caused by 'weak' epileptic discharges spreading along the cortico-reticular fibres and activating the motor inhibitory reticulospinal pathways 2).
Differential diagnosis
A patient harboring a parietal convexity tumor whose clinical and CT features were suggestive of a meningioma. Unexpectedly the tumor was a well-differentiated adenocarcinoma from colon cancer with a markedly PAS-positive intragland content represented by wide areas of mucoid degeneration. Brain metastases from colon cancer are usually late occurrences and it is extremely rare that the brain lesion to be discovered while the primary tumor is still unknown 3).
A case of cavernous hemangioma which developed in the parietal convexity is reported. Angiography reveals that the mass is located extra-axially in the parietal convexity and the middle meningeal artery feeds the tumor. The feature of tumor stain is pooling or laking of contrast medium which is partially visualized even 10 minutes after injection of contrast medium. CT findings are almost identical to those of meningioma 4).
Case reports
A 49-year-old female with a left parietal convexity meningioma associated with an acute subdural hematoma is described. She was admitted because of sudden onset of severe headache accompanied by nausea and vomiting. She was also confused, and 6 hours after admission she developed lethargy, right hemiplegia, and left mydriasis with no pupillary reaction to light. Computed tomography disclosed a round, extra-axial mass in the left parietal region; it was heterogeneously enhanced. Emergency craniotomy, performed after carotid angiography, revealed a tumor with a massive underlying subdural hematoma. The histological diagnosis was meningotheliomatous meningioma, and there were many meningothelial cells within the hematoma 5).
Case 1. Parietal convexity meningioma. Radiographics. 1986 Mar;6(2):288-91. doi: 10.1148/radiographics.6.2.3685492. PMID: 3685492.
A 61-year-old woman who complained of headache and numbness of the left hand. She received hysteromyomectomy 28 years before but had no past history of trauma of the head. She suffered from frequent profound pain in both orbits for one year, and she consulted a neighboring practitioner due to occurrence of numbness of the left hand and malaise. Then, CT scan revealed abnormalities, so that she was referred to our center. On admission, neurological oxamination revealed no abnormalities but plain X-ray film of the skull showed a round destruction in the right parieral bone. CT scan showed a round high density area of 3 cm in diameter in the right parietal region, this is markedly enhanced with contrast media. There is a crescent-shaped low density area extending forward from the high density area. The body of the right lateral ventricle is totally collapsed. Selective arteriography of the right external carotid revealed tumor stain in the parietal region. Therefore, under the diagnosis of association of chronic subdural hematoma and convexity meningioma, craniotomy of the right frontal, parietal and temporal regions was carried out and a meningioma of 10 g, and a subdural hematoma with its capsule touching the maningioma were entirely extirpated 6)
A 58-year-old female visited the hospital complaining of headache and occasional nausea on February 6, 1980. Plain and enhanced cT confirmed a large tumor in the right parietal region and three small tumor nodules in the right occipital region. Carotid angiogram detected only two tumors of frontal falx. Apparent two tumor stains were seen on the region, and they were fed by meningeal frontal and parietal region, and they were fed by meningeal arteries through the right ophthalmic artery. A large tumor of parietal and a small tumor of frontal region on the right side of falx were removed. Three nodular tumors of right occipital convexity were extirpated at the same time. Histological examination of the tumors disclosed all extirpated tumors were fibroblastic meningioma. Case 2. A 61-year-old male developed convulsive seizure of the right upper limb and right side of the face was diagnosed as having convexity meningioma in the left parietal region 7).
The first case was a 56-year-old female, whose complaints were motor weakness and hypesthesia on the right side. At the operation, a hen egg-sized tumor with a large cyst was removed totally from the left frontoparietal mid-convexity. Multiple cystic cavities were contained in the tumor. Histologically the tumor was compatible with meningocytic meningioma with angiomatous component and showed numerous myxomatous degeneration and swollen vessel walls. 2) The second case was a 17-year-girl complaining of headache, blurred vision, right hemiparesis and episodes of Jacksonian seizure. At the operation, a goose egg-sized tumor in the left parietal lobe was removed and the tumor contained a large cyst. Histologically the tumor was a malignant meningioma, associated with relatively fresh necroses adjacent to the cyst 8).
Ploncard P, Del Vivo RE, Klaiber R. Meningiochondroma of the cerebral convexity. Case report. J Neurosurg. 1972 Dec;37(6):735-40. doi: 10.3171/jns.1972.37.6.0735. PMID: 4654702.
JACKSON FE. Right convexity meningioma with associated shift of the calcified choroid plexuses: case report. BMQ. 1962 Sep;13:111-2. PMID: 14450584.