[Primary intraosseous cavernous hemangioma of the cranium: a case report]. / Pervichnaya vnutrikostnaya kavernoznaya gemangioma kostei cherepa: obzor literatury i opisanie klinicheskogo nablyudeniya khirurgicheskogo lecheniya.

Primary intraosseous cavernous hemangioma (PICH) is a rare benign vascular tumor. This neoplasm is common in the spine and less common in skull. Toynbee J. first described this tumor in 1845. PICH of the cranium does not always have typical X-ray features and should be always differentiated with other more common skull lesions. Surgical resection is preferable since total resection is followed by favorable prognosis. We present a 65-year-old patient with asymptomatic tumor of the right parietal bone. CT revealed osteolytic lesion that required total resection and skull repair. Histopathological analysis revealed intraosseous cavernous hemangioma.

[Diffusion tensor imaging tractography and intraoperative neurophysiological monitoring in surgery of intracranial tumors located near the pyramidal tract].

BACKGROUND: Practical application of methods for intravital examination of the brain pathways, such as preoperative diffusion tensor imaging (DTI) tractography and intraoperative neurophysiological monitoring, facilitates safer resection of intracranial tumors located near the pyramidal tracts (PTs). PURPOSE: The study purpose was to investigate the relationships between intracerebral tumors of different histological nature and the pyramidal tract based on preoperative DTI tractography and various methods of intraoperative neurophysiological monitoring for intraoperative identification of the pyramidal tract, depending on different variants of the topographo-anatomic relationships between the pyramidal fascicle and the tumor. MATERIAL AND METHODS: The study included 29 patients with supratentorial tumors of a different histological structure. Of these, 2 patients had grade I tumors, 8 patients had grade II tumors, 4 patients had grade III tumors, 11 patients grade IV tumors, and 4 patients had brain metastases. The patients underwent preoperative DTI tractography with PT reconstruction and evaluation of the topographo-anatomic relationships between the pyramidal tract and the tumor (tract: intact, infiltrated, displaced). Neurophysiological monitoring (direct electrical stimulation in 24 patients and transcranial motor evoked potentials in 26 patients) was used during surgery. The strength of stimulating current for direct stimulation was varied from 10 to 30 mA. Postoperatively, the motor function was evaluated by using a 5-score scale, and the data were compared to the preoperative data. RESULTS: According to preoperative DTI tractography in patients with grade I-II gliomas, the corticospinal tracts were infiltrated in 2 cases, displaced in 3 cases, and intact in 5 cases. In patients with grade III-IV gliomas and metastases, the tracts were infiltrated in 8 cases, displaced in 4 cases, and intact in 7 cases. Motor responses evoked by direct electrical stimulation were obtained in 5 out of 6 patients with the pyramidal tract displaced by the tumor and in 7 out of 8 patients with the tract infiltrated by the tumor. In the case of the intact tract, the PT to tumor distance and the stimulus strength play an important role: responses were obtained in 4 out of 10 patients. In the case of transcranial motor evoked potentials (TCMEPs), no dynamics of the potential amplitude was detected in 17 out of 26 patients during surgery; a reduced TCMEP amplitude was detected in 9 patients. CONCLUSION: 1. Patients with an infiltrated or displaced pyramidal tract had significantly more often hemiparesis before surgery and aggravation of hemiparesis after the surgery compared to patients with an intact tract. 2. In the case of direct electrical stimulation of the PT, motor responses (according to preoperative DTI tractography) were significantly more often observed for the pyramidal tract infiltrated and displaced by the tumor. 3. A reduction in the motor neurologic deficit in the postoperative period was significantly more often observed for application of a larger current strength during direct electrical stimulation. 4. Persistence of the TCMEP amplitude during surgery is a reliable predictor for no aggravation of the motor neurological deficit after surgery. Postoperative aggravation of hemiparesis was significantly more often observed when TC MEPs decreased during surgery.

[Transformation of trigeminal nerve tumor into malignant peripheral nerve sheath tumor (MPNST)].

Malignant peripheral nerve sheath tumor (MPNST) is a rare entity with only 18 cases of trigeminal nerve MPNST described by now and only one report of malignant transformation of trigeminal nerve tumor into MPNST published up to date. One more case of malignant transformation of trigeminal nerve (1st division) tumor into MPNST is demonstrated.

[Differential diagnosis between melanotic schwannoma of gasserian ganglion and metastatic melanoma of middle cranial fossa].

We present a case of a rare tumor--melanotic schwannoma of trigeminal nerve root and gasserian ganglion. Differential diagnosis between metastatic melanoma and melanotic schwannoma (MS) is associated with serious difficulties and high responsibility. Metastatic melanoma is a high grade tumor while most MS are benign lesions with good outcome. By the date 105 cases of these tumors are described in the world literature, 3 of them originated from trigeminal nerve root and gasserian ganglion. MS predominantly occur in relatively young patients, they are characterized by presence of Carney's complex and psammomatous bodies and absence of primary focus. MS and metastatic melanoma have similar appearance on MRI due to presence of melanin granules. Indirect signs evident for MS include cystic structure and dumbbell-shaped growth. Metastatic melanoma of cranial nerves is more typical in people older than 40, primary focus in the face in the zone of innervation of affected nerve is common. In case of absence of the listed features differential diagnosis is based on immunohistochemical analysis and electron microscopy of tissue samples.