Faculty Bibliography

Immunohistochemistry has revolutionized both the research and diagnostic endeavors of anatomic and surgical pathologists, including neuropathologists. These methods, which use the high specificity of antibody recognition of target antigens, have largely replaced the more capricious, less sensitive, and less specific panoply of metallic impregnations and other histochemical methods that once were characteristics of neuropathology. With immunostaining, specific infectious agents, from ordinary bacteria to spirochetes, fungi, parasites, and especially viruses, can be identified as the causative agents of central nervous system diseases. Understanding of the pathogenesis and establishment of correct diagnoses of neurodegenerative disorders are both improved, and more precise and reliable diagnosis of central nervous system tumors has become a matter of immunophenotypic characterization using panels of relevant antibodies to supplement the recognition of standard histologic patterns. Newer trends in neuropathologic immunohistochemistry point to a better understanding of the molecular pathology of degenerative disorders and of tumors as specifically mutated oncogenetic or neurotoxic antigens are localized and identified in diseased brain and spinal cord tissues

Cavernous angiomas of the internal auditory canal (IAC) are rare. They are angiographically occult; and because the clinical symptoms are similar both in intracanalicular cavernous angiomas and acoustic tumors it had been difficult to differentiate pre-operatively both of these pathologies until the advent of magnetic resonance imaging (MRI). Even nowadays the correct diagnosis may be missed if the patient is imaged only with gadolinium enhanced MRI without prior obtaining a non-contrast MRI. These diagnostic difficulties are illustrated by the report of a related case. The importance of thorough neuroradiological investigations stressed and MRI features, surgical management and relevant literature concerning the cavernous angiomas of the internal auditory canal are discussed

Clinical presentations as well as radiological and histopathological findings in biopsies from patients with multiple sclerosis (MS) or other demyelinating disorders of the central nervous system are sometimes misleading, resulting in an erroneous diagnosis of brain or spinal cord tumor. We report 17 patients who presented with symptoms mimicking those of brain (14 cases) or spinal cord (three cases) tumors. Computerized tomography or magnetic resonance imaging studies or both were interpreted as consistent with a tumor in each case. All patients underwent surgery, and all 17 pathological specimens were eventually diagnosed as showing demyelinating disease, usually consistent with MS. In each case we examined a variety of histological features and immunohistochemical studies and addressed their relative importance in considering the diagnosis of MS. All cases showed perivascular lymphocytic inflammation with variable amounts of macrophage infiltration, necrosis, and edema. The hypercellularity of the lesions and the presence of atypical reactive astrocytes with mitotic figures were the disturbing features that might have led to the erroneous diagnosis of an astrocytic neoplasm. Immunohistochemistry for astrocytic (glial fibrillary acidic protein) and macrophage (HAM-56) markers are helpful in evaluating biopsies. Our results emphasize the need to perform special stains (i.e., for myelin and axons) that demonstrate myelin loss and relative preservation of axons and allow a correct diagnosis

BACKGROUND. A malignant epithelioid hemangioendothelioma (EH) developed within a peripheral intramuscular lipoma. It was seen as a painful calf mass. At the time of biopsy and en bloc resection, lung metastases were observed. METHODS. Radiologic, histologic, immunohistochemical, and ultrastructural features of the neoplasm are described, and the literature pertaining to EH is reviewed. RESULTS. The features of this tumor permitted its classification as a malignant EH. CONCLUSIONS. This case illustrates the potential for aggressive behavior in an EH, often considered to be a low-grade malignant neoplasm. Because such tumors can metastasize, they should be removed with wide margins whenever possible. This malignant neoplasm was located within a benign intramuscular lipoma, demonstrating the diagnostic problem that may exist in such a complex lesion

Two cases of cystic brainstem schwannomas protruding into the fourth ventricle are described. Both patients presented with hemifacial spasm. While there is only one previous case report of an intraventricular brainstem schwannoma, there has been no prior description in the literature of hemifacial spasm associated with such a tumor. The clinical, radiographic, surgical, and histopathological features of these tumors are elaborated. The relationship of hemifacial spasm to the various putative theories of origin proposed for intraparenchymal schwannomas is discussed

A 13-year-old boy with Down syndrome (DS) had a brainstem glioma confirmed at autopsy, 10 years after receiving prophylactic cranial irradiation for acute myeloblastic leukemia. There is no clear association of brain tumors with DS; despite a reported link between leukemia and glioma, a causal association with radiation therapy is more likely