Intradural spinal tumors: current classification and MRI features.

The differential diagnosis of intradural spinal tumors is primarily based on location, but the clinical presentation, age, and gender of the patient are also important factors in determining the diagnosis. This comprehensive review focuses on the current classification, clinical symptoms, and MRI features of the more common intradural extramedullary and intramedullary neoplastic lesions. This review does not include extradural lesions.

Comparison between neuroimaging classifications and histopathological diagnoses using an international multicenter brain tumor magnetic resonance imaging database.

OBJECT: The aim of this study was to estimate the accuracy of routine magnetic resonance (MR) imaging studies in the classification of brain tumors in terms of both cell type and grade of malignancy. METHODS: The authors retrospectively assessed the correlation between neuroimaging classifications and histopathological diagnoses by using multicenter database records from 393 patients with brain tumors. An ontology was devised to establish diagnostic agreement. Each tumor category was compared with the corresponding histopathological diagnoses by dichotomization. Sensitivity, specificity, positive and negative predictive values (PPVs and NPVs, respectively), and the Wilson 95% confidence intervals (CI) for each were calculated. In routine reporting of MR imaging examinations, tumor types and grades were classified with a high specificity (85.2-100%); sensitivity varied, depending on the tumor type and grade, alone or in combination. The recognition of broad diagnostic categories (neuroepithelial or meningeal lesions) was highly sensitive, whereas when both detailed type and grade were considered, sensitivity diverged, being highest in low-grade meningioma (sensitivity 100%, 95% CI 96.2-100.0%) and lowest in high-grade meningioma (sensitivity 0.0%, 95% CI 0.0-65.8%) and low-grade oligodendroglioma (sensitivity 15%, 95% CI 5.2-36.0%). In neuroepithelial tumors, sensitivity was inversely related to the precision in reporting of grade and cellular origin; "glioma" was a frequent neuroimaging classification associated with higher sensitivity in the corresponding category. The PPVs varied among categories, in general being greater than their prevalence in this dataset. The NPV was high in all categories (69.8-100%). CONCLUSIONS: The PPVs and NPVs provided in this study may be used as estimates of posttest probabilities of diagnostic accuracy using MR imaging. This study targets the need for noninvasively increasing sensitivity in categorizing most brain tumor types while retaining high specificity, especially in the differentiation of high- and low-grade glial tumor classes.

Oral spindle cell neoplasms: a review of 307 cases.

The infrequent exposure of pathologists to soft tissue spindle cell neoplasms coupled with overlapping histologic patterns can often make diagnosis challenging. We reviewed all nonodontogenic spindle cell neoplasms seen between 1982 and 2002 (86,162 total accessions). Diagnoses were reclassified according to current standards supplemented with immunohistochemistry. Of the 307 neoplasms reviewed (0.36% of total accessions), neural tumors were the most common benign entities, accounting for 21% of total cases. Kaposi's sarcoma was the most common malignancy, accounting for 67% of all cases. Diagnoses were revised for 57 cases. Schwannoma and neurofibroma were most commonly revised to palisaded encapsulated neuroma. There were 8 myofibromas and 1 inflammatory myofibroblastic tumor. There were no oral leiomyomas; that is, all 4 originally reported cases were reclassified as myofibroma, palisaded encapsulated neuroma, and solitary fibrous tumor. With the exception of Kaposi's sarcoma, oral soft tissue sarcomas were rare; most benign lesions were neural in origin. The relatively high prevalence of some tumors, such as myofibroma, likely reflects the use of immunohistochemistry in the diagnosis of spindle cell tumors.

Malignant peripheral neuroectodermal tumor and its necessary distinction from Ewing's sarcoma. A report from the Kiel Pediatric Tumor Registry.

A new classification scheme is proposed for the differential diagnosis of Ewing's sarcoma and malignant peripheral neuroectodermal tumor (MPNT) based on conventional light microscopic and immunohistochemical findings. The presence of Homer-Wright rosettes and/or the expression of at least two neural markers is diagnostic of MPNT Ewing's sarcoma. Ewing's sarcoma was diagnosed in cases lacking Homer-Wright rosettes and expressing no neural marker or only one in immunohistochemistry. Using this "new" approach considerable differences were found between both tumor types. Although most MPNT were located in the thoracopulmonary region, Ewing's sarcoma was located predominantly in the pelvis and extremities. The mean age of MPNT patients was greater than that of Ewing's sarcoma patients. Most importantly, however, was a statistically significant difference in prognosis: disease-free survival in Ewing's sarcoma patients at 7.5 years follow-up was 60% compared with 45% MPNT patients (P = 0.026). The detection of HNK-1 in MPNT indicated a more aggressive biologic behavior, and the expression of protein S-100 appeared to be correlated with a more favorable clinical course.

Benign neoplasms of the oral cavity.

A wide variety of benign tumors present in the oral cavity. These tumors are for the most part rare and are classified by the tissue of origin. Although benign oral cavity tumors are not life-threatening, they can result in extensive loss of soft tissue and/or bone. Furthermore, many patients are subject to the threat of recurrence, multiple surgical procedures, and the possibility of malignant degeneration. Because many tumors vary little clinically, an adequate biopsy specimen must be obtained for diagnosis. Radiographs are, in general, nondiagnostic. Collaboration with an experienced pathologist is necessary to determine the tumor's probable clinical behavior. Therapy, which is dictated by tumor type, is almost always surgical.

Neurogenic tumors of the skin.

A classification of peripheral nerve sheath tumors in the skin is based on analysis of light-, electron microscopy, immunohistochemistry and cellular composition of the different tumor types. Not only Schwann cells, but also perineurial cells and fibroblasts may be involved in tumor formation. Schwann cell rich and connective tissue cell rich tumors are distinguished. Generally all tumors show low proliferating activity as investigated by H3-Thymidine autoradiography. Only in few connective tissue cell rich tumors higher labelling indices can be demonstrated. These findings are correlated with the clinical course and prognosis of the different tumor types. The question remains, whether connective tissue cell rich tumors are at higher risk for malignant transformation.

An appraisal of the World Health Organization classification of tumors of the central nervous system.

An important development in the classification of tumors of the central nervous system was the nomenclature recommended by the World Health Organization in 1979. Since then, wide usage has suggested that the classification be modified to account for problems that neuropathologists have encountered. Although no classification is ideal, modification of certain tumor categories, particularly from the perspective of childhood brain tumors, is desirable. These are discussed in detail. Greater emphasis on standardization of the localization of brain tumors is also recommended. This appraisal suggests changes that will allow a consensus on nomenclature of central nervous system tumors so that a workable classification is the end product.

Revision of the World Health Organization classification of brain tumors for childhood brain tumors.

A classification for childhood brain tumors based upon revision of nomenclature of all brain tumors published by the World Health Organization (WHO) in 1979 is proposed. Applicability of the WHO classification scheme was tested in a combined study of the clinical and pathologic features of approximately 3300 brain tumors in children. It was found to be adequate for many of the neoplasms but unsuitable for a significant proportion, including a number of complex cerebral tumors for which there was no appropriate name. Nomenclature of poorly differentiated or densely cellular neuroepithelial tumors was simplified to reflect the current state of knowledge of neuroembryology and neuro-oncology, although the Committee members recognized that such a proposal would likely perpetuate the long-standing and continuing controversy relative to the nature and origin of these neoplasms.

Tumours of the nervous system.

Tumours of the nervous system of animals are not as rare as has been commonly believed. In dogs, especially the brachycephalic breeds, these tumours occur as frequently as in man. The tumours are grouped according to tissue of origin as follows: nerve cells, neuroepithelium, glia, peripheral nerves and nerve sheaths, meninges and vessels, the pineal and pituitary glands, and the craniopharyngeal duct. Tumours of the glia are relatively common and are divided into the following types: astrocytoma, oligodendroglioma, glioblastoma, spongioblastoma, medulloblastoma, and unclassified gliomas.