Immunoreactivity of bovine schwannomas.

Thirty schwannomas from 22 cows were examined immunohistochemically. All were positive for vimentin and Ki-67 but negative for pancytokeratin, neurofilament, and desmin. S-100 immunolabelling varied between and within lesions. The numbers of tumours giving positive results for S-100, neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) were 16, 30 and 25, respectively. It was concluded that vimentin-positive tumours suspected to be schwannomas should also be immunolabelled for NSE and GFAP to confirm the diagnosis.

Morphometric evaluation of NB84, synaptophysin and AgNOR is useful for the histological diagnosis and prognosis in peripheral neuroblastic tumors (pNTs).

OBJECTIVE: To study the importance of NB84, synaptophysin and AgNOR and explore the quantitative association of these factors with diagnosis and outcome as well as the association between NB84 and AgNOR and other tumor and stromal factors in twenty-eight peripheral neuroblastic tumors. METHODS: We assessed AgNORs, NB84, synaptophysin and several other markers in tumor tissues from 28 patients with primary neuroblastic tumors. The treatment included: surgery for stage 1, chemotherapy and bone marrow transplantation for most of stages 3 and 4. Histochemistry, immunohistochemistry and morphometry were used to evaluate the amount of tumor staining for AgNOR, NB84 and synaptophysin; the outcome for our study was survival time until death due to recurrent neuroblastic tumors. RESULTS: Only stage (p<0.01), AgNOR (p<0.01), NB84 (p<0.01) and synaptophysin (p=0.01) reached statistical significance as prognostic indicators. CONCLUSIONS: Determination of NB84 and synaptophysin are useful tools for the diagnosis of peripheral neuroblastic tumors The association of the evaluation of AgNOR expression by the tumor cells may provide an important contribution to the prognostic evaluation and management approach of the patients.

Immune system evasion by peripheral nerve sheath tumor.

Mechanisms by which tumor cells evade detection by the host's immune system are thought to play a role in progression to malignancy, but this has not been investigated in the context of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant disorder, in which aggressive peripheral nerve tumors, known as malignant peripheral nerve sheath tumors (MPNSTs), develop in 5-10% of patients. Large scale gene expression profiling of a MPNST-derived cell line, T265, and normal human Schwann cells (hSCs) identified a large group of immune function genes down-regulated in T265 cells. Here we report that the aberrant expression of immune system related genes extends beyond MHC class I and II genes in T265 cells to include a transcription factor (MHC2TA) and other critical components of the antigen processing and presentation apparatus. TAP1, the transporter-activator protein that loads peptide antigens onto MHC class I molecules, is down-regulated, and CD74, a chaperone protein whose function is in processing and transport of MHC class II molecules, is down-regulated and alternatively spliced to produce an RNA transcript not evident in normal human Schwann cells. These findings reveal multiple molecular pathways and at least two cellular mechanisms acting to reduce the normal immune system molecules involved in antigen processing and presentation in cells derived from a peripheral nerve sheath tumor. Acquiring a "silent" immune signature may be a critical step in the progress towards malignancy in MPNSTs.

Use of s-100 and chromogranin a antibodies as immunohistochemical markers on detection of malignancy in aortic body tumors in dog.

To define the characteristics of malignancy we performed routine histology and an immunohistochemical study on seventeen aortic body tumors in dogs. We essayed tumors using a panel of immunohistochemical markers: neuron specific enolase (NSE), chromogranin A (CrA) and S-100. Among 17 cases, the neoplastic cells were positive for NSE (17 cases, 100%), S-100 (9 cases, 53%), and CrA (8 cases, 47%), respectively. The sustentacular cells density and chief cell staining intensity were both inversely related to tumor grade. The most relevant data was consistent with a negative staining of S-100 correlated with absence or decreased number of sustentacular cells in tumors grade III. This report indicates that the immunohistochemical panel has utility for the diagnosis of chemodectoma and the negative staining to CrA and S-100 markers in tumors grade III expresses an indication of malignant behaviour of the tumor.

[Non-Hodgkin's malignant lymphoma of the peripheral nervous system: clinicopathological correlations in ten patients]. / Lymphomes malins non Hodgkiniens du système nerveux périphérique. Corrélations anatomo-cliniques dans 10 observations.

INTRODUCTION: Identifying tumor infiltration or compression in patients with non-Hodgkin's malignant lymphoma presenting peripheral neuropathy can be a difficult task. METHODS: We collected a series of patients with peripheral neuropathy with demonstrated lymphomatous infiltration or compression managed between October 1977 and October 2001 to search for clinico-pathological correlations. RESULTS: Ten cases were reviewed. Neurological manifestations were the inaugural symptom of the disease in 7 patients. Clinical presentations included 5 focal (3 cranial nerve palsies, 2 brachial radiculopathies) and 5 diffuse neuropathies (3 polyradiculoneuropathies, 1 polyneuropathy and 1 mononeuritis multiplex). The mechanisms of peripheral nerve involvement were classified into lymphomatous meningoradiculitis (5 cases), involvement of cranial nerves or spinal roots in their extraneuraxial course (3 cases) and infiltration of distal peripheral nerves (2 cases). Four long lasting survivals after treatment were observed. CONCLUSIONS: Prognosis depends much more on the haematological disease than on the neurological symptoms or tumor location.

Demyelinating neuropathy due to primary IgM kappa B cell lymphoma of peripheral nerve.

A 53-year-old man presented with a painful, demyelinating sensorimotor peripheral neuropathy with lymphomatous infiltration on sural nerve biopsy, but no evidence of systemic lymphoma. The neuropathy responded to cytotoxic therapy. Seven years later he developed generalized lymphadenopathy due to B cell lymphoplasmacytoid lymphoma, with a subpopulation of cells expressing a monoclonal pattern of IgM kappa. The lymphomatous infiltrate in the original nerve biopsy showed similar monoclonal IgM kappa reactivity. The mechanism of demyelination of the peripheral nerves may be similar to that described in patients with IgM kappa monoclonal gammopathies.

The purely epithelioid malignant peripheral nerve sheath tumor.

The purely epithelioid malignant peripheral nerve sheath tumor (PNST) is a rare form of PNT possibly first described by McCormack et al. in 1954. This tumor type is distinguishable from the glandular PNT and PNT with differentiated neuroepithelium (medulloepithelioma and neuroepithelioma) and differs from the ordinary epithelioid PNT because of the absence of a spindle cell component typical of malignant PNSTs. The two examples of purely epithelioid malignant PNT we describe arose in the popliteal fossa from the sciatic and tibial nerves of men with no definite evidence of von Recklinghausen's neurofibromatosis. Both tumors were partly mucinous, and so closely mimicked carcinoma and a few non-neurogenic myxoid sarcomas histologically that their final classification depended upon proof of a neural origin.

Immunohistochemical detection of epithelial membrane antigen in normal perineurial cells and perineurioma.

The use of epithelial membrane antigen (EMA) as an immunohistochemical marker for normal and neoplastic perineurial cells is described. Normal perineurial cells react strongly for this antigen, which is also expressed by the cells of perineurioma. Instead, neurofibromas and schwannomas only show some peripheral or entrapped layers of EMA-positive cells. In traumatic and Morton's neuromas, bundles of neural fibers are wrapped in layers of EMA-positive perineurial cells. Neurothekeoma and granular cell tumor show no EMA reactivity. The detection of an epithelial marker in perineurial cells is in agreement with the concept of a "perineural epithelium" and seems to support a common embryologic origin for the perineurial cell and the equally EMA-positive arachnoidal cap cell. The availability of an immunohistochemical marker for the perineurial cell provides an easy and convenient tool for the evaluation of the participation of this cell in a variety of pathologic processes.

Immunoprofile of MITF, tyrosinase, melan-A, and MAGE-1 in HMB45-negative melanomas.

A majority of desmoplastic melanomas and some of the other forms of melanomas are S-100 positive and HMB45 negative; this pattern of immunoreactivity is similar to certain nerve-derived tumors such as malignant peripheral nerve sheath tumor. In this study the immunostaining profile of HMB45-negative malignant melanomas was evaluated by a panel of antibodies against markers associated with melanoma and melanocytic differentiation, including microphthalmia transcription factor, tyrosinase, Melan-A, and MAGE-1. Immunodetection was performed on paraffin sections of 22 cases of HMB45-negative malignant melanomas (including 8 spindle cell melanomas, 8 desmoplastic melanomas, and 6 epithelioid melanomas), 8 HMB45-and S-100-positive malignant melanomas, 15 malignant peripheral nerve sheath tumors, 16 schwannomas, and 11 neurofibromas. Of eight HMB45-positive malignant melanomas, all were positive for Melan-A, tyrosinase, and melanocyte-specific transcription factor, and three were positive for MAGE-1. In the 14 HMB-45 negative, nondesmoplastic melanomas, melanocyte-specific transcription factor was positive in 9, Melan-A in 9, tyrosinase in 6, and MAGE-1 in 11. In eight desmoplastic malignant melanomas, MAGE-1 was positive in three, and all other markers were negative. The five markers tested were negative in all but two schwannomas, one with focal melanocyte-specific transcription factor and the other with tyrosinase and weak MAGE-1 reactivity. MAGE-1, melanocyte-specific transcription factor, tyrosinase, and Melan-A are useful markers in the diagnosis of malignant melanocytic lesions when HMB45 is negative. MAGE-1 may be useful in differentiating melanocytic lesions from nerve-derived lesions, but its sensitivity is relatively low. The immunostaining profile of desmoplastic malignant melanomas more closely resembles that of malignant peripheral nerve sheath tumor than that of other types of malignant melanoma. Melanocyte-specific transcription factor is not a useful marker for desmoplastic melanoma.

Perineurioma: an uncommon soft tissue neoplasm distinct from localized hypertrophic neuropathy and neurofibroma.

Perineurial cells, which normally surround the nerve fascicles within a nerve, can be distinguished from Schwann cells by their immunoreactivity for epithelial membrane antigen (EMA) and lack of reactivity for S-100 protein. We report two cases of perineurioma, a tumor composed exclusively of perineurial cells and distinct from other nerve sheath tumors. The first case involved a deep, soft-tissue mass of the neck, and the second involved a tumor located in the infraclavicular subcutaneous tissue. Both tumors were well circumscribed. Histologically, they were hypocellular and composed of spindle cells possessing elongated nuclei and bipolar, wavy, slender, strikingly elongated cytoplasmic processes, disposed in a background of collagen in the form of short bundles and whorls. In the first case, there were frequent calcospherites and remnants of a small nerve at the periphery. The spindle cells stained for EMA but not S-100 protein, chromogranin, neuron-specific enolase or Leu-7. Ultrastructurally, they possessed long cytoplasmic processes with incomplete basal lamina and occasional pinocytotic vesicles. Axons were not identified. Review of the literature shows that genuine perineuriomas are rare, and most cases reported as such are merely examples of localized hypertrophic neuropathy, a mononeuropathy characterized by fusiform swelling of a nerve, usually in the extremities. The involved segment in localized hypertrophic neuropathy contains distended fascicles composed of whorls of perineurial cells and fibrous tissue entrapping residual axons, probably representing a hyperplastic reaction to nerve damage. The term perineurioma should be reserved for the neoplasm composed only of perineurial cells and presenting as a soft tissue tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

CD-34 is expressed by a distinctive cell population in peripheral nerve, nerve sheath tumors, and related lesions.

The pattern of CD-34 antigen (human progenitor cell antigen) immunoreactivity was studied within normal nerve, and a variety of nerve sheath and neuroectodermal tumors. Besides normal nerves, 111 soft tissue tumors were studied, including 17 neurofibromas, 10 neurilemomas, 12 malignant peripheral nerve sheath tumors, 1 melanocytic schwannoma, 21 fibroblastic lesions, 31 fibrohistiocytic lesions, seven neuroectodermal lesions, and 10 miscellaneous tumors. CD-34-positive dendritic cells were consistently identified within the endoneurium of normal nerve, all neurofibromas, dermatofibrosarcomas, and Antoni B (but not Antoni A) areas of neurilemomas. CD-34 was not expressed in the majority (eight of 10 cases) of malignant peripheral nerve sheath tumors. CD-34 was also lacking in all fibroblastic lesions (nodular fasciitis, fibromatosis, keloid, fibrosarcoma) and in neuroectodermal tumors that are not generally considered to show true nerve sheath differentiation (neurotropic melanoma, clear cell sarcoma, neuroepithelioma). We conclude that CD-34 (or a closely related epitope) defines a normally occurring nerve sheath cell that appears to be cytologically and immunophenotypically distinct from a fibroblast and conventional Schwann cell. The antigen can also be localized to benign nerve sheath tumors, but tends to be lost in malignant ones. The consistent presence of CD-34 within all 13 cases of dermatofibrosarcoma protuberans can be used as evidence in support of the view that these lesions are variants of nerve sheath tumors, and distinct from benign fibrous histiocytomas which consistently lack the antigen. Finally, expression of CD-34 by one of three giant cell fibroblastomas reinforces the close relationship between this tumor and dermatofibrosarcoma protuberans.

An immunohistochemical study of human central and peripheral nervous system tumors, using monoclonal antibodies against neurofilaments and glial filaments.

Monoclonal antibodies that recognize either neurofilaments or glial filaments were used with the peroxidase-antiperoxidase (PAP) method to retrospectively study 100 tumors of the central and peripheral nervous systems in paraffin-embedded sections. Only neoplasms of putative neuronal origin or with presumed neuronal differentiation (paraganglioma, ganglioglioma, ganglioneuroblastoma, ganglioneuroma, neuroblastoma, ovarian teratoma and pheochromocytoma) contained tumor cells with immunoreactive neurofilament, but such cells were more common in the more differentiated or benign neoplasms in this category. Glial filament immunoreactivity was observed in tumor cells of glial origin and in tumor cells with foci of glial differentiation arising within the central nervous system, consistent with findings from previous studies using anti-glial-filament antisera. With the exception of a benign cystic teratoma, no glial filament immunoreactivity was observed outside the central nervous system. Some immunoreactive neurofilaments, but not glial filaments, were arranged in presumably abnormal balls, cords, or clumps within tumor cells, possibly reflecting cytoskeletal alterations related to neoplastic transformation. These findings indicate that monoclonal antibodies against intermediate filament proteins such as neurofilaments and glial filaments retain their specificity and sensitivity when employed in paraffin sections in conjunction with the peroxidase-antiperoxidase method. They suggest that such reagents are useful probes for the evaluation of the histogenesis or degree of differentiation in human nervous system tumors. Finally, they permit the speculation that the analysis of the intermediate filaments of tumor cells, as contrasted with those in normal cells, may provide new insights into the biology of neoplasms.

What are the CD34+ cells in benign peripheral nerve sheath tumors? Double immunostaining study of CD34 and S-100 protein.

To determine whether CD34 expression in nerve sheath lesions was found in a unique cell population or in a subset of nerve sheath cells, we performed double immunohistochemical staining using a standard avidinbiotin complex method with 2 separate color developing systems. We studied 40 neurofibromas and 16 neurilemomas. All lesions strongly expressed S-100 in nuclei and cytoplasm. CD34 was detected in cells having ameboid dendritic cytoplasm present in greatest numbers in Antoni B zones of neurilemomas, myxoid zones of neurofibromas, at the periphery of lobules in both tumor types, and condensed in apposition to perineurium. The CD34+ cells also were detected in normal nerves. They were infrequent in Antoni A zones of neurilemomas. No dual S-100 and CD34 expression was seen. This double immunostaining confirms the presence of a CD34-reactive non-Schwannian cell type in these neural neoplasms. As the CD34+, S-100-negative cell population is present also in normal nerves and infrequently seen in the areas of cellular neoplastic Schwann cells, CD34+, S-100-negative cells in peripheral nerve sheath tumors most likely are nonneoplastic and may have a supportive function.

Paraganglioma of the cauda equina. A histologic, immunohistochemical, and ultrastructural study and review of the literature.

We report a case of paraganglioma of the cauda equina and filum terminale. Diagnosis was established by the histologic organoid pattern, immunohistochemical staining for neuron-specific enolase and ultrastructural dense-core neurosecretory granules. A survey of the literature yielded 16 previously reported cases, five of which were described in 1983. This suggests that heightened awareness of this entity will result in a corresponding increase in the reported incidence.

Amyloidoma of the brachial plexus.

BACKGROUND: Amyloidomas of the peripheral nervous system are rare lesions. Most commonly, they involve the gasserian ganglion and the branches of the fifth cranial nerve. No association with systemic amyloidosis has been reported. CASE DESCRIPTION: We describe an amyloidoma of the lower trunk of the right brachial plexus. At the age of 34 years, this 71-year-old female had undergone radical right mastectomy for breast cancer with axillary lymph node dissection followed by radiotherapy. On admission, she presented with burning pain to the right hand and mild motor deficit to the ulnar-innervated intrinsic hand muscles. A palpable lesion was found in the supraclavicular region. On surgical inspection, the lesion appeared to originate from the lower trunk of the right brachial plexus. The middle and upper trunks were dislocated. Histologically, fibrous connective tissue embedded small nerve bundles featuring perineurial and endoneurial fibrosis as well as amyloid. Amyloid featured immunoreactivity for both lambda and kappa chains. DISCUSSION: Localized amyloidoma of brachial plexus has never been reported. Because of compressive rather than infiltrative growth of the present lesion, a conservative surgery was achieved. Our immunohistochemical findings indicated that peripheral nerve amyloidomas are not, by definition, monoclonal in nature.

Malignant epithelioid peripheral nerve sheath tumor arising in a benign schwannoma.

The case of a patient with malignant degeneration of a solitary abdominal schwannoma and endobronchial metastasis is presented. The patient presented clinically with dyspnea referable to her lung mass, anorexia, and night sweats. The lung mass, initially diagnosed as a large-cell undifferentiated carcinoma, was later found to be histologically identical to the malignant portion of the abdominal tumor. The light microscopic, electron microscopic, and immunoperoxidase staining characteristics of the tumor are reported, and previous reports in the literature are reviewed.

CD25+ regulatory T cell inhibition enhances vaccine-induced immunity to neuroblastoma.

Evidence that CD4CD25 regulatory T (Treg) cells play a role in the progression of cancer continues to mount. There is a great deal of interest as to whether transient elimination or functional inhibition of these cells can improve the efficacy of immunotherapy for cancer. Our goals in this study were to test whether treatment of mice with anti-CD25 monoclonal antibody (mAb) (PC61) could induce rejection of a murine neuroblastoma, whether anti-CD25 treatment could increase tumor immunity when administered just before cell-based vaccination, and to learn how anti-CD25 treatment influences the vaccine-induced antitumor response. Treatment of mice with anti-CD25 mAb induced rejection of the mouse neuroblastoma, Neuro-2a, as 90% of anti-CD25-treated mice survived challenge with a lethal dose of tumor cells. In vivo anti-CD25 mAb treatment before the first of 2 weekly vaccines significantly improved the survival of tumor-vaccinated/challenged mice (75% vs. 33% survival), whereas antibody treatment before each of the 2 vaccines did not, suggesting that excessive treatment with anti-CD25 mAb interferes with activated antitumor effector cells. A detailed phenotypic analysis of tissues from anti-CD25-treated mice indicated that the antibody partially depletes CD4Foxp3 Treg cells (25% to 40%) in A/J mice, and that the antibody may inhibit the remaining cells by inducing loss of CD25 expression and blocking CD25 molecules, partially confirming recent data from other investigators. Importantly, we found that in vivo anti-CD25 mAb treatment significantly decreased the contribution of asialo GM1 cells in the antitumor response. As we did not see a direct effect of anti-CD25 mAb on in vitro assays of immune cell function in spleen cells from treated animals, this indicates that inhibition of Treg cells amplifies the immune response in vivo in a manner that bypasses the requirement for innate immune activation, potentially mediated by natural killer cells, and allows for protective CD4 and CD8 cells to expand directly in response to cell-based vaccines.

Immunohistochemical recognition of human nerve sheath tumors by anti-Leu 7 (HNK-1) monoclonal antibody.

Using relatively high dilutions of anti-Leu 7 monoclonal antibody and a four-step peroxidase-antiperoxidase (PAP) reaction in paraffin-embedded tissues, we tested the affinity of this antibody to the cells of 47 human nerve sheath tumors and 22 other tumors in which the differential diagnosis with nerve sheath neoplasms is known to arise. Of all the nerve sheath tumors studied 68%, including 80% of the schwannomas, contained anti-Leu 7-positive cells. All 22 non-schwannian neoplasms were entirely negative. Specimens of eight experimental malignant rat schwannomas were also negative for anti-Leu 7 antibody. Our findings suggest that anti-Leu 7 monoclonal antibody is a promising marker that may facilitate the differential diagnosis between human Schwann cell and non-Schwann cell neoplasms.

Distribution of Thy-1 differentiation alloantigen in the rat nervous system and in a cell line derived from a rat peripheral neurinoma.

The expression of the Thy-l 'differentiation alloantigen' was analyzed in rat tissues of two strains. Cerebrum was shown to express an amount of Thy-l equivalent to the thymus. The cerebellum, brain stem and spinal cord expressed approximately one-half this amount, and the olfactory bulb expressed 10- to 15-fold less. Of the peripheral nervous system tissues examined, only cauda equina expressed substantial amounts of Thy-l, although minor amounts were found on the lumbar roots and trigeminal nerve. Kidney, spleen, liver, salivary gland and testes expressed little or no Thy-l. Several cell lines derived from nervous system tumors were also examined. RN-l, a line established from a rat peripheral neurinoma, expressed Thy-l at levels comparable to thymus.

Intraneural biphasic synovial sarcoma: an alternative "glandular" tumor of peripheral nerve.

A primary intraneural biphasic synovial sarcoma that arose within the common digital nerve of the hand is reported. The patient, a 16-year-old girl, presented with a small soft tissue mass that clinically and intraoperatively resembled a nerve sheath tumor. The diagnosis of synovial sarcoma was established on the basis of a typical light microscopic appearance and immunohistochemical staining profile. Intraneural biphasic synovial sarcoma resembles "glandular" peripheral nerve sheath tumor, because both are composed of a mixture of spindled mesenchymal cells with admixed glandular epithelial elements. The features allowing differentiation of these two unusual tumors of peripheral nerve are discussed.