A recurrent vagal schwannoma in the middle mediastinum after surgical enucleation.

A 50-year-old man underwent repeat surgery for a benign vagal schwannoma in the middle mediastinum. He had undergone tumor enucleation at another hospital 4 months before presentation. The tumor (99 × 88 × 76 mm) was located in the aortopulmonary window and arose from the left vagus nerve. It had been enucleated, leaving its sheath behind to preserve the nerve. Imaging studies showed tumor regrowth without distant metastasis, and the tumor was extirpated along with the involved nerve during cardiopulmonary bypass. There was no nerve dysfunction, recurrence, or metastasis 6 months after the operation. A benign vagal schwannoma can be excised with nerve transection or enucleated without nerve transection. The present case suggests that a vagal mediastinal schwannoma should be extirpated along with the nerve because insufficient enucleation might lead to tumor regrowth.

[Olfactory ensheathing cell tumour: case report and literature review]. / Tumor de las células envolventes del olfatorio: caso clínico y revisión de la literatura.

Olfactory ensheathing cells are glial cells located in the olfactory bulb and nerve. Microscopically, both olfactory ensheathing cells and Schwann cells have similar morphological and immunohistochemical features. However, olfactory ensheathing cells are negative for Leu-7(CD-57), whereas Schwann cells are positive. We present the case of a 49 year-old male with a history of visual impairment and hyposmia. Radiological CT and MRI studies showed a subfrontal cystic extra-axial mass, which eroded the right cribriform plate, with heterogeneous contrast enhancement. Total excision of the tumour was performed by bifrontal craniotomy. Histological examination initially suggested a schwannoma, with immunohistochemical staining being positive for S-100 protein and negative for epithelial membrane antigen (EMA). However, the tumour was negative for Leu-7. Accordingly, the final diagnosis was olfactory ensheathing cell tumour. Herein, we describe the sixth case of intracranial olfactory ensheathing cell tumour and stress the important role of immunohistochemical techniques in obtaining a definitive diagnosis.

[Standardizing a central nervous system tumor DNA biobank]. / Estandarización de un biobanco de ADN de tumores del sistema nervioso central.

BACKGROUND: Brain tumors are one of the leading cancers worldwide; in the National Institute of Neurology and Neurosurgery (INNN) these tumors are the leading cause of morbitity and mortality. OBJECTIVE: Standardize biopsies, colletion, processing and storage biologic material of molecular studies. METHODS: with a previously signed surgical consent, a tumor and blood biopsy was done to 134 patients. Their DNA was extracted and a database was filled considering technical, ethical and legal aspects. In order to have optimal biologic material the procedure was standardized between the surgical and research laboratory teams. RESULTS: The biopsy, transportation, processing and storage were standardized. 134 patients were included (67 male and 67 female) with an average age of 46.28 years (range 15-81). The most frequently biopsied tumor was the meningioma (42%). The integrity of the obtained material was determined by agarose gel electrophoretic analysis. CONCLUSION: the INNN biobank has a standardized system that biopsies, processes and stores optimum quality biologic material that will be the basis of future molecular studies.

Squamous cell carcinoma presenting as an orbital cyst with radiologic evidence of perineural invasion.

PURPOSE: To report clinical and radiologic findings of cystic squamous cell carcinoma (SCC) of the orbit with evidence of perineural involvement. METHODS: Analysis of clinical findings and radiology with a literature review. RESULTS: A 66-year-old man with SCC of the forehead 8 years prior presented with paraesthesias, diplopia, and proptosis. Magnetic resonance imaging showed a well-defined, cystic mass of the orbit with a single, linear structure running through its center. Lateral orbitotomy revealed a cyst adherent to adjacent periorbita containing viscous, clear, yellow substance and a nerve coursing through the center. Histopathology confirmed poorly differentiated spindle cell carcinoma with positive staining for cytokeratin markers, consistent with SCC. CONCLUSIONS: Orbital cysts associated with altered sensation are suggestive of SCC with perineural spread, requiring prompt investigation and treatment to minimize morbidity and mortality. The involved nerve may be seen as a single, linear structure within the mass on imaging.

Cytokeratin expression in adrenal phaeochromocytomas and extra-adrenal paragangliomas.

AIM: To examine whether adrenal phaeochromocytomas and extra-adrenal paragangliomas are immunoreactive for commercially available and routinely used cytokeratin antibodies. METHODS: 18 extra-adrenal paragangliomas and seven adrenal phaeochromocytomas were stained with CAM 5.2, AE1/3, and 34 beta E12 following microwave antigen retrieval of formalin fixed tissue. RESULTS: A single case from the cauda equina was positive for both CAM 5.2 and AE1/3. In addition, two other cases--an intravagal and an orbital paraganglioma--also showed strong immunopositivity with CAM 5.2 and AE1/3. All phaeochromocytomas were negative with all epithelial markers. CONCLUSIONS: Cauda equina paragangliomas are known to stain with cytokeratins; however, occasional paragangliomas from other sites may also be immunoreactive with cytokeratins. If the results of immunohistochemistry are not interpreted in the clinical and morphological context, the failure to recognise that extra-adrenal paragangliomas may on occasion react with anticytokeratin antibodies may lead to their being confused with metastatic carcinomas.

Neuropeptide immunoreactivity in ligature-induced neuromas of the inferior alveolar nerve in the ferret.

Injury to branches of the trigeminal nerve can sometimes result in persistent dysaesthesia. In an attempt to understand the aetiology of this condition we are currently investigating changes which occur at the injury site. In the present study we have examined the expression of seven neuropeptides, all of which have been implicated in nociceptive transmission, or have previously been shown to have altered expression following nerve injury. In 20 adult ferrets the inferior alveolar nerve was sectioned and ligated, and recovery permitted for 3 days, 8 days, 3 weeks, 6 weeks or 12 weeks. Longitudinal sections of the neuromas were processed using immunohistochemical techniques to quantify the expression of substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, galanin, somatostatin, enkephalin and neuropeptide Y. After 3 days, all of the neuropeptides were expressed at the injury site. In the neuromas examined after longer recovery periods these levels of expression had declined and were similar to those found in the contralateral controls. This initial high level, followed by a decline, parallels the incidence of ectopic neural activity recorded electrophysiologically in the same model. It is, therefore, possible that the accumulation of neuropeptides at the injury site may play a role in the initiation or modulation of ectopic neural activity.

Epithelioid Schwannoma of the acoustic nerve.

A 25-year-old woman presented with left progressive deafness due to an intracranial tumor of the cerebello-pontine angle. Biopsy and subsequent total surgical excision indicated origin from the acoustic nerve. Histologically, the tumor showed typical feature of Schwannoma associated with a population of epithelioid cells. Three years after surgery no local invasion, no relapse, and no metastasis were noted. Immunohistochemistry showed a strong positivity for S100 protein in the cytoplasm of Schwannian and epithelioid tumoral cell components. This positivity in the epithelioid cells correspond to a well differentiated cell population derived from a Schwann cell precursor explaining the benign course of the tumor. In the absence of similar cases of epithelioid Schwannoma of the acoustic nerve in literature, we will discuss the differential diagnosis, potential evolutivity, and origin of the epithelioid cells.

Rapid growth of an optic nerve ganglioglioma in a patient with neurofibromatosis 1.

BACKGROUND: Optic nerve gangliogliomas are extremely rate tumors of the central nervous system composed of elements of glial and neuronal origin. The clinical and biologic behavior of gangliogliomas depends on the glial component. Pilocytic gangliogliomas generally have a low growth rate and good ultimate prognosis. No definitive relation has yet been established between gangliogliomas and neurofibromatosis type 1. METHODS: The authors describe the clinical, histologic, and immunohistochemical features of an optic nerve ganglioglioma with several atypical findings. A review of the literature is provided. RESULTS: An optic nerve glioma was diagnosed in a 16-year-old patient who had signs of neurofibromatosis type 1; the atypical clinical course involved a rapid progression of symptoms with a significant increase in tumor size. The tumor was removed surgically and found to be a ganglioglioma composed of pilocytic glial cells (immunoperoxidase-positive for glial fibrillary acid protein) and neurons (immunoperoxidase-positive for neuron specific enolase, synaptophysin, and neurofilament). A focal astrocytic area showed increased cellularity, several mitotic figures, and an elevated labeling index with Ki-67 immunoperoxidase staining. CONCLUSION: Optic nerve gangliogliomas are rare tumors that cannot be distinguished clinically from pilocytic astrocytomas. Although these tumors usually grow slowly, careful follow-up is advised. The atypical histologic features are considered to be a manifestation of rapid local growth rather than a harbinger of malignant behavior. The authors' findings suggest that gangliogliomas may be included in the diagnostic criteria for neurofibromatosis type 1.

Histiocytic tumor of Meckel's cave. An intracranial equivalent of juvenile xanthogranuloma of the skin.

We present the case of a 7-year-old boy who had a solitary mass within Meckel's cave that recurred 6 weeks after the initial resection. The histological, immunohistochemical, electron-microscopical, and molecular genetical features established the lesion's histiocytic nature. Our findings showed that it was closely related to juvenile xanthogranuloma, a benign lesion that usually occurs in the skin but has not yet been histologically confirmed in the brain. The present tumor is different from other intracranial histiocytic and xanthogranulomatous lesions.

Benign nerve sheath tumors: a light microscopic, electron microscopic and immunohistochemical study of 102 cases.

One hundred and two cases of benign nerve sheath tumors (NSTs) were studied with a combined approach using routine light microscopy (LM), immunohistochemistry (IH) for myelin basic protein (MBP) and S-100 protein as well as transmission electron microscopy (TEM) with the aim of obtaining greater insight into the true nature of these neoplasms, and also to establish the importance of IH and TEM in their diagnosis. Myelin basic protein was not identified in any of these tumors, whereas S-100 protein was positive to a variable degree in both schwannomas and neurofibromas. TEM revealed that Schwann cells predominated in tumors which were strongly positive for S-100 protein and appeared as schwannomas by LM. However, neurofibromas showing a variable patchy positivity for S-100 were composed of an admixture of Schwann cells, fibroblast-like cells and intermediate cells considered to be modified Schwann cells. Perineurial cells in typical form were not seen. It is concluded that all NSTs are basically of Schwann cell origin and that the intermediate cells and fibroblast-like cells are variants of Schwann cells. The different morphological appearances and biological behaviour of schwannomas and neurofibromas may be related to some other factors like micro-environment or genetic predisposition. Further, both IH, especially for S-100 protein, and TEM play an important role in establishing their diagnosis.

Immunohistochemical localization of vimentin and S-100 antigen in small acoustic tumors and adjacent cochlear nerves.

To clarify the involvement of cochlear nerves in small acoustic tumors, we used immunoperoxidase techniques to determine the presence and distribution of vimentin and S-100 antigens in two acoustic tumor specimens and a transected vestibular nerve. Schwann cells and acoustic tumor cells failed to react positively with monoclonal antibody to vimentin. Reaction was observed in mesenchymal-appearing cells within both the normal nerve and the acoustic tumors, predominantly in association with blood vessels. Normal schwann cells and acoustic tumor cells reacted with polyclonal antibody to S-100 antigen with a similar, uniform distribution. Mesenchymal-appearing cells did not react with antibody to S-100. Immunostaining of a vestibular nerve from a Meniere's disease patient, used as a control, did not differ significantly from nerves adjacent to acoustic tumors. Because tumor cells and normal schwann cells stained similarly with antibody to S-100, it was not possible to establish with certainty if tumor cells invaded adjacent nerves.

Immunohistochemical investigations in experimentally induced tumors of the nervous system.

35 tumors of brain, spinal cord and cranial and peripheral nerves were induced with ENU (ethyl-nitrosourea) in the offspring of treated BD-IX pregnant rats. 36 tumors--35 of the nervous system, one nephroblastoma--were observed in 14 rats. With these results, the number of experimental nervous system tumors of the own collection induced in BD-IX rats and classified next to the rules of human neurooncology, amounts to 2,216. All 35 tumors of the nervous system were treated by a panel of immunohistochemical reactions comprising antibodies against cytoskeleton intermediary filaments such as GFAP (glial fibrillary acid protein), neurofilament proteins, vimentin and cytokeratins and some nervous system antigens such as NSE (neuron specific enolase), MBP (myelin basic protein) and S-100 protein. In central tumors, considered to be malignant gliomas, focal reactivity against vimentin and GFAP was found. Expression of other tested markers was weak or absent. In neurinoma of trigeminal and peripheral nerves, reactivity to S-100 antigen was lacking, whilst there was strong reaction to the vimentin antigen.