Marc G. Reyes

Spinal extradural angiolipoma: A report of two cases and review of the literature

Extradural angiolipomas are rare tumors that can produce spinal cord compression. Two patients with thoracic spinal angiolipoma are presented that were treated with surgical resection and radiation. The histological and clinical features of the 18 previously reported cases of these tumors are discussed.

Imprints, smears, and frozen sections of brain tumors.

In this study, we compared the suitability and accuracy of imprints, smears, and frozen sections of suspected brain and spinal cord tumors of 150 patients. Eighty-six percent of the imprints, 91% of the smears, and 99% of the frozen sections were suitable for interpretation. Among the suitable preparations, 82% of the imprints, 92% of the smears, and 99% of the frozen sections agreed with our diagnosis on paraffin sections. Although frozen sections were clearly more accurate than imprints and smears, the latter two provided diagnoses in patients with acquired immunodeficiency syndrome where frozen sections were not done to avoid contaminating our cryostat and in a patient with an epidermoid cyst of the middle fossa that could not be adequately frozen sectioned. Our study shows that imprints and smears complement frozen sections in the intraoperative diagnosis of tumors of the central nervous system.

Diagnostic accuracy of AIDS-related CNS lesions

Because of the high incidence of neurological complications seen in patients with acquired immunodeficiency syndrome (AIDS), an increasing number of these cases are being referred to neurosurgeons for consideration of intracranial biopsy. To better determine the need for biopsy in these patients we evaluated the accuracy of non-tissue-based neurological diagnoses in AIDS patients who subsequently had a final diagnosis on the basis of biopsy or postmortem brain examinations. The records of 56 AIDS patients who had undergone either autopsy or brain biopsy were retrospectively reviewed. Of the ten patients who underwent biopsy, three were found to have a lesion that was different from the suspected diagnosis and that resulted in a change in treatment. Thirty patients with neurological symptoms had postmortem brain examinations. In the case of the 12 patients who had carried specific diagnoses and received treatments based on those diagnoses, only six diagnoses (50%) were proven correct at autopsy. Of the 18 cases that did not record a specific antemortem diagnosis, in only 5 were normal brains reported, while the others reported a variety of nonspecific or infectious findings. Twelve patients without neurological symptoms had postmortem brain examinations and only six of these (50%) had normal or slightly atrophic brains. Case reports of the others noted nonspecific findings most of which were suggestive of subacute HIV encephalitis. The poor rate of diagnostic accuracy in this series suggests that biopsy should be considered for atypical lesions or those that do not respond to empiric therapy. The use and relative sensitivities of various diagnostic studies are also discussed.

Decreased nigral neuromelanin in Alzheimer's disease

Abstract Using manual morphometric techniques, we estimated the amount of neuromelanin in hematoxylin and eosin-stained sections of the pars compacta of the substantia nigra of 19 Alzheimers patients without nigral Lewy bodies and 12 age-matched controls. Our estimates showed that the mean area and areal fraction of neuromelanin were lower in Alzheimers disease than controls but the number and size of the neuronal cell bodies, nuclei and nucleoli did not differ between the two groups. We speculated that the decreased amount of neuromelanin in nigral neuronal cell bodies could have resulted from neurofibrillary degeneration, retrograde degeneration from damage of nigral dopaminergic terminals in the striatum by the beta amyloid protein of the diffuse plaques and possibly transneuronal degeneration from damage of cell bodies or dendrites of nigral neurons by their plaque- and tangle-ravaged striatal, neocortical and other subcortical nigral connections. We hypothesized that any or all of the above types of degeneration could have lowered the rate of dopamine metabolism and the formation of one of its by-products, neuromelanin. Our study shows that a decrease in the amount of histopathologically-observable nigral neuromelanin commonly occurs in Alzheimers disease without nigral Lewy bodies.

Malignant lymphoma presenting as a chronic subdural hematoma

A 56-year-old man had a right frontotemporoparietal craniotomy for evacuation of an encapsulated subdural hematoma that had reaccumulated after burr-hole decompression 6 weeks before. Histopathologic examination showed a malignant lymphoma in the subdural hematoma. Our patient shows that malignant lymphoma can rarely present as a chronic subdural hematoma.

Aneurysmal bone cyst of the thoracic spine: treatment by excision and segmental stabilization with Luque rods.

Preoperative radiological evaluation with magnetic resonance imaging and computed tomography was valuable in planning the surgical management of a destructive lesion of the posterior elements of the thoracic spine that was causing spinal cord compression in an 18-year-old woman. Preoperative recognition of bilateral involvement of the pedicles in addition to the laminae and spinous process led to use of prophylactic segmental stabilization of the spine with Luque rods after successful excision of an aneurysmal bone cyst. This case provides an example of the usefulness of computed tomographic scanning and magnetic resonance imaging in assessing the distribution and location of vertebral tumor and its potential effect on spinal stability. The efficacy of combining radical excision with stabilization for treatment of aneurysmal bone cysts of the spine is emphasized.

Malignant schwannoma (neurofibrosarcoma) metastatic to spine. Surgical decompression and stabilization.

We report a case of a patient with pulmonary metastases as well as T8 and T9 vertebral body metastases causing compression fracture and epidural spinal cord compression