A case of infected schwannoma mimicking malignant tumor.

BACKGROUND: Infected schwannoma has been reported, this being one of the four cases published in the literature. Infected schwannoma has proven to be a tough diagnostic challenge to the treating tumor surgeon, mimicking infectious entities and most essentially, a malignant tumor. CASE PRESENTATION: The authors report the case of a 64-year-old male with a soft tissue mass in his right gluteal area that presented initially with right leg pain, then later with signs of inflammation on the tumor area. Magnetic resonance imaging (MRI), computed tomography (CT), and thallium-201 scintigraphy studies confirm the presence of soft tissue mass which had continuity with sciatic nerve, with subsequent serial MRI findings suggesting tumor enlargement with cystic degeneration. Increased level of C-reactive protein (CRP) was observed before surgery. During an open biopsy upon tissue sampling, exudates with necrotic tissue were seen. Increased level of CRP and necrotic change suggested the possibility of malignant tumor. Histopathological diagnosis was schwannoma, and group B Streptococcus was detected by culture. After the confirmation of infected schwannoma, enucleation of the tumor was performed. CONCLUSIONS: The report concludes that establishment of a benign pathology is essential when presented with similar clinical findings prior to definitive enucleation of an infected schwannoma.

Corneal infection by Pseudomonas stutzeri following excision of trigeminal nerve schwannoma.

A 25-year-old woman underwent intracranial surgery for trigeminal nerve schwannoma (TGNS) with persistent left-sided facial hypoaesthesia. Two months later, she developed a central corneal ulceration. Scraping of the corneal lesion revealed Gram-negative bacilli. Genus level identification was achieved using standard techniques and species level identification, revealing Pseudomonas stutzeri, was aided by a VITEK 2 compact system. Broad-spectrum fortified antibiotics were initially started followed by species-sensitive fortified antibiotics. Ocular surface toxicity developed a week later; this was managed with a non-fortified antibiotic. The epithelial defect healed in 3 weeks with subsequent corneal scar formation. Visual rehabilitation was achieved with deep anterior lamellar keratoplasty. Six months following surgery, the patient had a visual acuity of 20/40 with -1.25 170° -0.5 refractive correction and a clear graft. This case report, for the first time, highlights P. stutzeri, an aetiological agent of corneal ulcer following excision of TGNS and its successful management.

Aspectos histoquímicos e imunoistoquímicos nos neoplasmas do sistema nervoso periférico / Histochemical and immunohistochemical features of peripheral nerve neoplasms

Doze casos de tumores do sistema nervoso periférico, sete schwannomas e cinco neurofibromas foram diagnosticados entre 1964 e 2004, em caninos e bovinos. Histologicamente, as células predominantes nos schwannomas eram fusiformes organizavam-se em paliçada ou em feixes aleatórios. Nos neurofibromas as células neoplásicas eram fusiformes e se originavam da periferia dos nervos formando ninhos e feixes. O tecido conjuntivo era mais abundante nos neurofibromas e os colágenos dos tipos I e III eram os principais constituintes desses neoplasmas. Os neurofibromas foram caracterizados por uma concentração alta e difusa de mastócitos, provavelmente devido à origem das células neoplásicas do perineuro e epineuro. A coloração de AgNOR não se mostrou eficiente como indicador de prognóstico nos neoplasmas analisados. Imunoistoquímicamente houve forte marcação para vimentina (100 por cento) e S100 (100 por cento) em ambos os tipos de tumor. A maioria dos schwannomas (75 por cento) foi positiva para a proteína ácida fibrilar glial; os neurofibromas só apresentaram marcação nas células de Schwann dos fascículos nervosos

A retrospective study of peripheral nerve tumors was made from 1964 to 2004. The tumors summed up 12, being seven schwannomas and five neurofibromas. Schwannomas were composed of spindle-shaped cells either in a palisading pattern or random bundles loosely textured and neurofibromas by spindle cells. The connective tissue components were more prevalent in neurofibromas with a characteristic deployment of collagens type I and III. In AgNOR techniques, both benign and malignant schwannomas and neurofibromas did not show differences. Mast cells stained by toluidine blue were more prevalent in neurofibromas which are rich in reactive endoneurium. Schwannomas (100 percent) and neurofibromas (100 percent) were positive for vimentin and S100 protein, so they prove to be reliable for the diagnosis of peripheral nerve tumors. GFAP marked cells were found in three schwannomas and in Schwann cells within neurofibromas

In vivo and in vitro models of demyelinating diseases. XII. Persistence and expression of corona JHM virus functions in RN2-2 Schwannoma cells during latency.

The coronavirus JHMV persistently infects rat Schwannoma cells RN2-2 at 32.5 degrees C and enters a host-imposed reversible, latent state at 39.5 degrees C. JHMV can remain up to 20 days in the latent state and about 14 days before the cultures lose the capacity to resume virus production upon return to 32.5 degrees C. Although persistently and latently infected RN2-2 cells display resistance to superinfection by a heterologous agent VSV, these cells do not release detectable soluble mediators (e.g., interferon) of the antiviral state. Nevertheless, RN2-2 cells are competent to synthesize and release interferon when treated with the appropriate inducers. These observations suggest that interferon does not play any role or may not be the major factor in the control of latency in the Schwannoma cell. Hybridization with virus-specific cDNAs shows that all viral mRNAs are present during latency and that viral mRNAs are present in the polysomes of infected cells at 39.5 degrees C. Western immunoblotting with hybridoma antibodies demonstrates that viral specific proteins are produced at the restrictive temperature. These results suggest that despite the absence of production of infectious virus at 39.5 degrees C, there is active transcription and translation into virus-specified products.

In vivo and in vitro models of demyelinating disease X. A Schwannoma-L-2 somatic cell hybrid persistently yielding high titres of mouse hepatitis virus strain JHM.

Following infection of RN2 rat Schwannoma cells with unfiltered JHMV inocula, a cell line with an altered phenotype evolved, which was shown to be a somatic cell hybrid of RN2 and mouse L-2 cells. This cell line, EJ, persistently yields JHMV at titres greater than 10(6) pfu/ml and does not show the suppression of virus production at 39.5 degrees C that is characteristic of a persistently infected RN2 line. Intracellular viral nucleocapsids are demonstrated. Cloning of EJ hybrids yields cell lines that show a variety of responses to infection by JHMV or MHV3.

Particles with RNA of high molecular weight and RNA-directed DNA polymerase in human brain tumors.

We have previously shown that neoplastic cells of human breast cancers, leukemias, lymphomas, and sarcomas contain particles similar to the viruses that have been established as etiologic agents of these diseases in mice. The present paper concerns tumors of the central nervous system for which no suitable animal model or corresponding virus exists. Nevertheless, using the simultaneous detection test, we showed that human brain tumors contain 70S RNA and RNA-directed DNA polymerase encapsulated in a particulate component possessing a density of 1.17 g/ml. These particles satisfy the three diagnostic criteria that characterize RNA tumor viruses of animals. 24 Out of 26 (92%) of the most malignant (glioblastoma and medulloblastoma) brain tumors examined contained these virus-like entities.