[Multiple cerebral abscess caused by Nocardia brasilientis].

Streptococcus aureus, streptococci, and enterobacteria were major causative agents of abscesses of the brain. At present, associated infection is responsible for 60% of cerebral abscesses. When systemic and specific immunities are diminished, a risk for cerebral abscesses caused by fungi increases. Among them, there are the most common fungi Candida species or Aspergillus species. The paper gives an example of successful complex treatment of multiple cerebral abscesses caused by an association of Nocardia brasiliensis and Staphylococcus epidermidis. The specific feature of the observation was the correct diagnosis before intraoperative verification of cerebral abscesses. The disease developed in the presence of diminished systemic immunity and in the absence of specific immunity to Nocardia. Immunodeficiency could be caused by prior herpetic infection, Epstein-Barr disease, a wasp bite. The pathogen that was able to cause microstrokes played an indubitable role in the pathogenesis of the disease, which predisposed to the development of cerebral abscesses in patients with immunodeficiency. Impaired blood circulation in the occipital region could be also induced by wasp venom.

[Malignant transformation of epidermoid cyst]. / Zlokachestvennaia transformatsiia épidermoidnoi kisty.

The paper presents a rare case of malignant transformation of an epidermoid cyst to the keratinizing type of squamous cell carcinoma. In a 47-year-old female patient with severe visual disturbances, MRI scans revealed a large supracellular tumor spreading to the third ventricle and medial portions of temporal lobes. The tumor was removed. A histological study of its biopsy specimen showed signs of both a benign process (epidermoid cysts) and its malignant epidermoid degeneration to the keratinizing type of squamous cell carcinoma. After 12-month combined therapy there was a continuous tumor growth with a significant dissemination within the base of the skull. The pathogenesis of epidermoid cysts, possible causes of malignant transformation, modalities of treatment and prognosis are briefly discussed.

[Surgical treatment of cholesteatomas (epidermoid cysts) of the posterior cranial fossa]. / Khirurgicheskoe lechenie kholeastom (épidermoidnykh kist) zadnei cherepnoi iamki.

In 1985 to 2000, the Academician N. N. Burdenko Research Institute of Neurosurgery, Russian Academy of Medical Sciences, examined and operated on 78 patients with epidermoidal cysts of the posterior cranial fossa. A complex of clinical symptoms of epidermoidal cysts of the posterior cranial fossa and their computed tomographic (CT) and magnetic resonance imaging (MRI) scans were studied. Based on clinical and X-ray evidence, their diagnosis was correctly made in 87.2% of cases. A procedure was developed for radical removal of epidermoidal cysts of the posterior cranial fossa. The stages and surgical treatment policy were elaborated. Total tumor removal was made in 81.25% of the patients. In other cases, a part of a capsule was left due to its close relationship to the adjacent neurovascular structures. Two patients with epidermoidal cysts of the cerebellopontile angle who had undergone radical tumor removal died in the immediate postoperative period. The cause of the two patients were ischemic attack in the brain stem. The quality of surgical treatment was assessed by examining changes in the patients' neurological status, CT and MRI evidence prior to surgery and in different periods after it. Recent radiological studies and microsurgical techniques completely ensure radical removal of epidermoidal cysts of by yielding a good postoperative outcome.

[Retrosigmoid suboccipital access]. / Retrosigmovidnyi suboktsipital'nyi dostup.

Retrosigmoid suboccipital access has been widely used in neurosurgical care for more than a century. It has been employed in different vascular diseases and tumors of the brain. The authors provide examples of how to use the retrosigmoid suboccipital access, a patient's position during its application and techniques. All stages of performance of the access, including trepanation of the internal acoustic meatus, are considered in detail. Emphasis is laid in the advantages and disadvantages of this access. The basic stages of the access are illustrated. Correct application of the retrosigmoid suboccipital access is stated to yield a good view of primarily the cerebellopontile angle and causes no its associated complications.

[Plastic repair of a defect in the base of the skull with soft tissues from the orbit after the removal of an extensive esthesioneuroepithelioma]. / Plastika defekta osnovaniia cherepa miagkimi tkaniami glaznitsy posle udaleniia rasprostranennoi éstezioneiroépiteliomy.

The paper describes a clinical observation of closure of sphenoidal sinus defect and plastic repair of dura mater by using orbital tissues after removal of a tumor from the medial portions of the middle cranial fossa, which spread into the orbit and sphenoidal sinus, in complete irreversible loss of visual function, ophthalmoplegia and ptosis in a patient with skull soft tissue hypotrophy due to multiple operations and radiation therapy and hence unsuitable for displacement and closure. This observation shows it possible to use orbital soft tissue for repair of the base of the skull, in cases when integumentary cranial tissues are impossible to use as a plastic material due to their hypotrophicity. At the same time severe dysfunctions, such as blindness and ophthalmoplegia enable orbital tissues to be employed without significantly deteriorating any functional and cosmetic effect.

[An approach to an esthesioneuroblastoma of the anterior cranial fossa via the anterior wall of the hypertrophied frontal sinus]. / Dostup k éstezioneiroblastome perednei cherepnoi iamki cherez peredniuiu stenku gipertrofirovannoi lobnoi pazukhi.

A 40-year-old patient with anterior cranial fossa esthesioblastoma was operated on. Surgical approach via anterior wall of enlarged frontal sinus was used. After removal of tumor from anterior cranial fossa, ethmoidal and frontal sinuses, skull base defect was closed with abdominal fat and periosteum. Different approaches to anterior cranial fossa are discussed.