Gonzalo Bravo

Cavernomas of the Brain

Our clinical and surgical experience with 16 cases of cavernous hemangioma (cavernoma) of the brain is presented. In 50% of the cases, symptoms appeared during the 3rd decade of life. The clinical picture included seizures in 50% of the cases and a brain tumor-like syndrome in 37.5%, and 12.5% of the cases began with an intracerebral hemorrhage. In our series females predominated over males by 2:1. Computed tomographic (CT) scanning is the best procedure for the diagnosis of cavernomas. However, exact preoperative diagnosis of these lesions is infrequent because cavernomas are generally accepted to be very rare. A slightly hyperdense nodule, poorly enhanced after contrast administration, is the prominent feature on the CT scan. A small, hypodense zone surrounding the lesion and calcifications within the nodule are also found. An excellent result after operation was obtained in all cases of cavernoma located in the brain hemispheres. In deeply placed cavernomas (basal ganglia or brain stem), the surgical prognosis is doubtful, and features such as the size of the lesion and its anatomical location are important.

Estrogen- and progesterone-receptor proteins in intracranial tumors

Estrogen and progesterone receptors have been measured in 13 intracranial tumors (eight meningiomas, two acoustic neurinomas, one primary tumor of neuroectodermal origin, one giant-celled glioblastoma, and one metastasis of carcinoma). Evidence is provided of the presence of progesterone receptors in meningiomas (87.5%). We could not find clear evidence of estrogen receptors in any tumor of this series. Presence of progesterone receptors in meningiomas suggests an explanation for the greater incidence of these tumors in women and their rapid growth during pregnancy.

Arachnoid cysts of the posterior fossa.

A series of 6 patients with arachnoid cysts of the posterior fossa who were treated surgically is presented. The diagnosis of the nature of the lesion and of the exact location within the posterior fossa could not be established on a clinical basis. CT scanning is the best method for diagnosing the lesion and for observing the postoperative evolution. Treatment consisted of removing the cyst walls, shunting the cyst to the peritoneum, or both. The differential diagnosis of arachnoid cysts of the posterior fossa from other cerebrospinal fluid collections, such as the megacisterna magna or the Dandy-Walker malformation, are discussed.

Recurrence in a different location of a cerebral arteriovenous malformation in a child after radiosurgery

Abstract The case of a 9-year-old girl with a right parietal arteriovenous malformation (AVM) of the brain obliterated after gamma knife (GK) radiosurgery with subsequent regrowth in a different site is reported. As far as we know, this is the first reported case of regrowth of an AVM in a different location after radiosurgery in a child. This situation has to be considered within the context of causes of unsuccessful treatment of AVMs with radiosurgery and justifies angiographic monitoring of pediatric patients until they reach adulthood.

Symptomatic glial cysts of the pineal gland

Two cases of symptomatic glial cysts of the pineal gland are reported. An origin similar to that proposed for paraventricular glial cysts of the brain is accepted. These unusual lesions could be considered in the differential diagnosis of cystic pineal masses.

Computed tomography with craniopharyngiomas: A review

A retrospective study of the computerized tomographic (CT) examinations of 20 children and 13 adults with craniopharyngiomas was undertaken, with special attention paid to the densitometric characteristics of the tumors (contrast enhancement and presence of cysts and calcifications). The aim was to quantify these characteristics and to assess their diagnostic reliability, both alone and together. In suprasellar tumors al three characteristics were present in 75% of the cases, with a diagnostic accuracy of 100%; two were present in 20.6%, with a diagnostic accuracy of 85%; and one was present in 3.4%, with a diagnostic accuracy of 50%. The unusual densitometric presentations of intrasellar tumors are discussed.

Traumatic false aneurysms of the middle meningeal artery.

The authors report a rare case of traumatic false aneurysm of the middle meningeal artery associated with a delayed contralateral extradural hematoma. The extradural hematoma was evacuated, and the pseudoaneurysm was removed to avoid delayed rupture. The literature on traumatic aneurysms is reviewed.

Meningiomas of the posterior fossa

Clinical and surgical results in 38 cases of posterior fossa meningiomas are presented. All cases have been diagnosed and operated upon during the last 12 years in this department. We have identified five locations for these tumors: cerebellopontine angle, cerebellar convexity, tentorium, peritorcular, and clivus. Clinical features of these tumors and their surgical management are described. Sixty-eight percent of the cases presented have been diagnosed by computed tomography scan. All cases were operated upon with a 15.78% postoperative mortality; 36.85% of the patients remained symptom-free; 26.32% suffered mild neurological deficits; and 21.05% suffered severe neurological deficits. Total resection had been accomplished in 84.22% of the cases. Computed tomography scans allow earlier and more accurate diagnosis of these tumors, which in our opinion has modified the surgical results for the better. We discuss our findings and compare them with other published articles.

Morphological study of human epileptic dendrites.

We studied 14 human epileptogenic foci with light and electron microscopy to establish their morphological patterns. Using silver staining techniques, we found dendritic areas devoid of spines, dendritic angulations, and nodular or segmentary dendritic swellings. When these findings were compared with the morphology of nonepileptic cortex, only the existence of dendritic swellings in the epileptic tissue was significant. Electron microscopy showed that the nodular dendritic swellings were due to an alteration in the normal arrangement of the microtubules. We hypothesize that an alteration in the microtubular arrangement causes a mechanical distortion of the dendritic membrane and subsequently may cause its depolarization.

EARLY ELECTROENCEPHALOGRAPHIC OBSERVATIONS FOLLOWING CHEMOPALLIDECTOMY

During our first electroencephalographic observations of parkinsonian patients who had been subjected to pallidal lesions for alleviation of tremor and rigidity (choroidal artery ligation; transtemporal or transfrontal chemopallidectomy), we observed that in some cases, besides the local transitory changes at the point of insertion of the needle, there were certain modifications in the electrical activity of the whole hemisphere of the brain. The actual significance of these changes remained questionable. This first group of patients was not homogeneous, as they had been subjected to different procedures. There was also variation in other factors, e.g., in the length of time between the operation and the electroencephalographic recording, and in the electroencephalographic technique. A routine standardized electroencephalographic study was planned in order to investigate: a) whether or not transcortical implantation of a chemopallidectomy catheter would be followed by paroxysmal rhythms initiated at the point of the cortical lesion, even if this lesion were minimal; b) possible changes in the electricalactivity of the cortex as a result of the destruction of the globus pallidus; and c) the correlations, if any, between the preoperative and postoperative electrical activity of the brain. For measuring electrical activity we used the scalp electroencephalogram. The clinical results of the operation were measured by the immediate neurologic response.