Faculty Bibliography

OBJECTIVE: Isolated intramedullary spinal cord or cauda equina involvement by sarcoidosis is quite rare. We report three patients with intraspinal sarcoidosis and absent systemic manifestations of the disease. The clinical presentation, operative management, electrophysiologic studies, pathology, laboratory investigations, and current therapy are discussed with attention to the previous literature. METHODS: Two of the three patients had a preoperative diagnosis of a cervical intramedullary spinal cord tumor. The third patient had the preoperative diagnosis of an infectious process involving the cauda equina. Magnetic resonance imaging (MRI) with gadolinium did not suggest an inflammatory process. Intraoperative somatosensory evoked potential performed in two patients exhibited normal amplitudes, but a prolonged latency in seven out of eight extremities; with normal central conduction time suggesting a peripheral or radicular involvement. All three patients underwent laminectomy and biopsy of the intraspinal pathology. RESULTS: Pathologic examination demonstrated sarcoidosis in all three patients. Intraoperative observations, intramedullary nodules, and thickening of the meninges were inconsistent with neoplasm and limited the surgical procedure to a biopsy. Frozen sections performed at two of the operations revealed an inflammatory process that confirmed the intraoperative observations. Postoperatively, the diagnostic work-up for all patients was negative for systemic manifestations. CONCLUSIONS: Isolated intraspinal sarcoidosis is a rare process. The current management for intramedullary spinal cord or cauda equina sarcoidosis is prolonged corticosteroids. The surgeon should not attempt complete resection if this granulomatous process is suspected

Calcification, as a feature of the vasculopathy, is a common pathological finding in children with acquired immunodeficiency syndrome. Large and small blood vessels of many organs including brain, heart, lungs, kidneys, liver, and spleen are affected. We report a case with calcification in multiple organs that was most prominent in the cardiac and skeletal muscle cells and the blood vessels of the cerebrum. To our knowledge, calcification of this degree has not been documented previously in a human immunodeficiency virus-infected child

Meningiomas are the second most common tumor to involve the cerebellopontine angle (CPA), but controversy exists as to whether they can arise within the internal auditory canal (IAC) or whether involvement of the IAC occurs secondarily by extension from the CPA. This paper reports on a patient with an enhancing IAC meningioma that then grew and on subsequent scans was found to involve the CPA. This case demonstrates that these tumors can arise within the IAC and can grow out to involve the CPA. These findings are discussed within the context of meningioma tumor genetics and the histologic evidence for precursor cells in the IAC. The radiologic findings useful in distinguishing an acoustic neuroma from a meningioma are reviewed in the light of this case. While an enhancing mass projecting into the IAC is most often an acoustic neuroma, this radiologic findings is not pathognomonic

OBJECTIVE AND IMPORTANCE: Although the differential diagnosis of intracranial lesions in patients who have tested positive for human immunodeficiency virus is extensive, toxoplasmosis, lymphoma, and progressive multifocal leukoencephalopathy comprise approximately 90% of such cases. Cytomegalovirus infection of the central nervous system may be difficult to diagnose and rarely presents as mass lesions revealed by radiographic studies. CLINICAL PRESENTATION: Two patients who had tested positive for human immunodeficiency virus presented with progressive focal neurological deficits. Radiographic studies revealed solitary contrast-enhancing lesions in the right basal ganglia and right cerebellar hemisphere, respectively. INTERVENTION: The first patient underwent a stereotactic biopsy but died despite appropriate therapy. The second patient died without tissue having been obtained for diagnosis. Postmortem examinations revealed necrotizing lesions with diffuse areas of infiltrating histiocytes containing eosinophilic cytomegalovirus inclusion bodies. CONCLUSION: Although rare, cytomegalovirus infection should be considered in patients who have tested positive for human immunodeficiency virus and who present with enhancing intracranial lesions

OBJECTIVE: Tenascin-C (TN) is an extracellular matrix glycoprotein with a characteristic six-armed structure. The aim of this study was to determine whether the concentration of TN in the cyst fluid of brain tumors can be used as a marker for angiogenesis and glioma grade. METHODS: We investigated the expression of TN in the cyst wall and cyst fluid of human brain tumors by immunohistochemistry, immunoprecipitation, and immunoblotting. The tumors included 12 astrocytomas (5 glioblastoma multiforme tumors, 1 anaplastic astrocytoma, 1 low-grade astrocytoma, 4 juvenile pilocytic astrocytomas, and 1 mixed glioma), 2 dysembryoplastic neuroepithelial tumors, 3 craniopharyngiomas, 2 ependymomas, 2 metastatic carcinomas, 3 arachnoid cysts, 1 glial ependymal cyst, and 1 inflammatory cyst. RESULTS: We detected no expression of TN in the cyst fluids of the ependymomas, craniopharyngiomas, and nonpilocytic low-grade astrocytoma. By contrast, TN was detected in the cyst fluids of all the other tumors. Results of quantitative immunoblotting using a PhosphorImager unit (Molecular Dynamics, Sunnyvale, CA) revealed that, on average, a 5-fold higher signal was observed in the glioblastoma multiforme tumors as compared with the anaplastic astrocytoma, and a 10-fold higher signal as compared with the mixed glioma, juvenile pilocytic astrocytomas, and dysembryoplastic neuroepithelial tumors. Results of TN immunohistochemistry in the astrocytomas correlated with glioma grade, with stronger staining of the hyperplastic vessels and tumor cells being observed in higher grade gliomas. No TN immunoreactivity was detected in the walls of the ependymomas, arachnoid cysts, and glial ependymal cyst that lack hyperplastic vessels, and minimal TN immunoreactivity was observed in the perivascular gliotic rim of the craniopharyngiomas. No TN was detected in the cyst fluid of these cystic processes. CONCLUSION: The presence of TN in and around the hyperplastic vessels and tumor cells present in the cyst walls of astrocytomas and its deposition in the intratumoral cyst fluid in which angiogenic factors have been detected further suggests a role for TN as an angiogenic modulator. These preliminary results suggest that immunodetection of TN in the tumor cyst fluid may indicate tumor type and grade

Tenascin-C (TN) is an extracellular matrix glycoprotein expressed during embryogenesis. Its distribution is restricted in normal adult tissues and is upregulated in tumors and inflammatory conditions. Twenty-five specimens were studied, including 7 reactive vascular lesions (6 cases of granulation tissue and 1 case of bacillary angiomatosis), and 18 vascular tumors (6 angiosarcomas, 7 hemangioendotheliomas, and 5 AIDS-related nodular type Kaposi's sarcomas). Formalin fixed-paraffin-embedded tissues were stained with monoclonal antibody to TN (DAKO) and with MIB-1 (AMAC). Heterogeneous expression of TN immunoreactivity was seen in all cases, with a diffuse pattern in bacillary angiomatosis and most granulation tissue cases and a focal pattern in angiosarcoma and most hemangioendothelioma cases. Kaposi's sarcoma cases showed both a focal and diffuse pattern of distribution. In most cases proliferation indices (PI) did not correlate with TN expression. Electron microscopy demonstrated active angiogenesis in bacillary angiomatosis and granulation tissue and vasculogenesis in angiosarcoma and hemangioendothelioma. The study demonstrated positive TN expression in reactive lesions with angiogenesis (granulation tissue and bacillary angiomatosis) and neoplastic lesions showing vasculogenesis (angiosarcoma and hemangioendothelioma), although with a different pattern of distribution. These results suggest that TN might be an important extracellular matrix glycoprotein in angiogenesis and vasculogenesis

A 36-yr-old man with AIDS exhibited intense 201Tl uptake (lesion-to-brain uptake ratio 5.38) in a brain lesion previously detected by MRI and CT. The lesion was biopsied and found to contain cells with viral inclusions diagnostic of cytomegalovirus infection, not tumor as the thallium SPECT results suggested. Thallium-201 SPECT may be less specific than previously reported for differentiating neoplastic disease from opportunistic infections in AIDS patients

OBJECTIVE AND IMPORTANCE: Intracerebral schwannomas not associated with cranial nerves account for less than 1% of surgically treated schwannomas of the central and peripheral nervous system. Subfrontal schwannomas are extremely rare, with only 15 cases reported to date. CLINICAL PRESENTATION: A 33-year-old man presented with a 4-month history of progressive headaches and lethargy. Radiographic studies revealed a large subfrontal tumor thought to be a meningioma preoperatively. INTERVENTION: The patient underwent a craniotomy for resection of his tumor. Intraoperatively, a large extra-axial tumor arising from the floor of the left frontal fossa was encountered. CONCLUSION: Microscopic examination of the tumor revealed a schwannoma. Several theories on the possible origin of intracerebral schwannomas have been considered. Because of the age of the patient at presentation, many authors have postulated a developmental origin for these lesions. However, extra-axial schwannomas not associated with cranial nerves often present later in life, suggesting a different pathogenesis for this subgroup

Ependymomas are rare central nervous system (CNS) neoplasms that occasionally disseminate along the neuraxis or to extraneural sites. Definitive criteria predictive of dissemination have yet to be determined. One hundred forty patients with CNS ependymoma (88 primary spinal and 52 primary intracranial tumors) were surgically treated by the senior author (F.J.E.) between 1986 and 1994. Sixteen patients (11.4%) demonstrated tumor dissemination. The disseminated group consisted of 11 (12.5%) of 88 primary spinal and five (9.6%) of 52 primary intracranial ependymomas. The authors retrospectively reviewed the patients with CNS ependymoma and have identified several characteristics associated with dissemination from the primary tumor site. The mean time from diagnosis to dissemination was 6.8 years. The patients with disseminated disease were younger (16.8 vs. 28.3 years old, p = 0.02), had fewer gross-total resections (29% vs. 68%, p = 0.015), and had tumors with higher proliferative indices (MIB-1 staining, 13.14% vs. 2.06%, p = 0.02). High-grade tumors had a mean proliferation index of 21%, versus 2.4% and 1.6% for myxopapillary and low-grade tumors, respectively (p = 0.0003). In contrast to previous studies, tumor histology was the most significant variable for time to dissemination as determined by multivariate analysis (p = 0.008). Myxopapillary and high-grade tumors were 3.6 and 5.6 times more likely to have a shorter time to dissemination than low-grade tumors. In addition, dissemination is associated with a worse prognosis. At follow-up review, 31% of patients with disseminated disease had died compared to 7% of patients without dissemination (p = 0.04). It is concluded that younger patients with subtotal resections, myxopapillary or high-grade histology, and tumors with high proliferative indices are at substantial risk for the development of disseminated disease during their clinical course