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At least 73 records · Page 4Linked to original sources

Pathology of acoustic nerve Schwannoma in vivo and in vitro.

The ultrastructural pattern of the acoustic nerve Schwannoma was studied on surgically excised tumours and on explants cultured in vitro. The typical neoplastic cell is elongated, spindle-shaped, coated with basement membrane and numerous protruding cellular processes. Cells demonstrating numerous microfilaments are also seen, sometimes intermixed with the typical spindle-shaped cells. Fibroblasts are not uncommon; nor are cells with a round nucleus and rich in organelle cytoplasm, resembling endothelial cells. Numerous collagen fibres and "Luse bodies" are seen in the extracellular space, especially in areas of low cellularity. Round or ovoid cells partially coated with basement membrane are not uncommonly seen in various areas of the neoplasm. In culture, several cells demonstrate fibrillary cytoplasm and long thin cellular processes are frequently seen. Unusual features, such as enwrapping of the cytoplasmic processes forming laminated myelin-like figures are occasionally seen in the surgical specimens as well as in the in vitro cultured explants.

Cells, Cultured↗

Laminin promotes differentiation, adhesion and proliferation of cell cultures derived from human acoustic nerve schwannoma.

The influence of laminin on cell cultures derived from unilateral acoustic nerve schwannomas was investigated. Cell cultures were initiated from 12 schwannomas, removed via the enlarged middle cranial fossa approach. Tumor tissue was dispersed by collagenase treatment and cells seeded in uncoated or laminin-coated culture dishes. Confluent cultures were immunocytochemically characterized with antibodies against S-100, CD 68, factor VIII-related antigen and type IV collagen. Cell adhesion in response to different doses of laminin was evaluated with an electronic cell counter. The effect of laminin on cell proliferation was assessed by measuring the incorporation of 5-bromo-2'-deoxy-uridine (BRDU) into cellular DNA. Cells cultured on laminin as substrate appeared more differentiated with long, fusiform, cytoplasmic processes. Cultured cells stained positive for S-100, not for factor VIII-related antigen or CD 68. Only cells cultured on laminin deposited a dense extracellular network of type IV collagen. When laminin was added to the culture medium, cell attachment and proliferation was stimulated in a dose dependent manner. Maximal stimulation of both was observed with a laminin concentration of 50 micrograms/ml, which induced a nearly 2-fold increase in cell attachment and an approximately 66% increase in DNA content. Since laminin is a major component of the extracellular matrix in schwannomas, the possibility exists that laminin is also mitogenic for human neoplastic Schwann cells in situ.

Adult↗

A modified extended middle cranial fossa approach for acoustic nerve tumors. Results of 125 operations.

During the past 10 years, 125 operations for acoustic nerve tumors were performed on 114 patients at the authors' institution using a modified extended middle cranial fossa approach. This approach is based on a combination of King and Morrison's translabyrinthine-transtentorial approach and on the extended approach through the middle cranial fossa described by Bochenek and Kukwa. There were two hospital deaths (operative mortality 1.6%). In 102 operations on the initial tumor, total removal was performed in 89 cases (87%), and in 71 (80%) of these the facial nerve was anatomically preserved. Intracranial end-to-end anastomosis was performed on five of the 18 sacrificed facial nerves; a facial-hypoglossal anastomosis was carried out in the remaining 13 patients and in five (7%) of the 71 patients whose anatomically preserved facial nerve functioned poorly. In seven (39%) of the 18 patients in whom an attempt to preserve hearing was made, postoperative hearing was saved. In 23 operations on 17 patients for recurrent tumors, most of which had previously been removed subtotally via the suboccipital approach, total removal was accomplished in 13 (57% of the 23 reoperations and 76% of the 17 patients). At reoperation, the facial nerve was preserved in six (55%) of the 11 patients in whom the facial nerve had not been sacrificed. Postoperative leakage of cerebrospinal fluid occurred in 11 cases (8.8%), with rhinorrhea in 10 cases and otorrhea in one. Five of the fistulas were corrected by surgery and the rest healed spontaneously. Other complications were not significant.

Adolescent↗

Melanotic schwannoma of the acoustic nerve.

Melanotic schwannoma is a rare neoplasm, with only 23 previously reported cases. We report an additional case of a melanotic schwannoma arising from the acoustic nerve in a 74-year-old man who had a probable forme fruste of neurofibromatosis. We briefly review the literature of this neoplasm and discuss theories regarding the histogenesis of these tumors.

Aged↗

Malignant triton tumor of the acoustic nerve. Case report.

The authors present the clinical, radiological, pathological features, and autopsy findings of a patient with malignant triton tumor of the acoustic nerve, which probably arose from a pre-existing acoustic schwannoma. The term "malignant triton tumor" is applied to malignant schwannomas with rhabdomyoblastic differentiation. A cerebellopontine angle tumor with spinal drop metastasis occurred in this patient 10 months after near-total removal of the original tumor.

Female↗

Gas-CT cisternography for detection of small acoustic nerve tumors.

Gas-CT cisternography is a simple and accurate procedure for detection of small acoustic nerve tumors. Review of one of the largest series in a single institution found that 98% of the studies clearly showed the presence or absence of tumors. The diagnostic pitfalls of the small number of studies in which significant errors were made, or could have been made, are discussed. It is concluded that certain situations appear to call for extra caution: (a) when the filling defect does not show a convex surface, (b) when the amount of cisternal gas is marginal, and (c) when the canal is small. In such situations careful attention to details and healthy skepticism may avert potential errors.

Adolescent↗