Diagnostic efficacy of stereotactic biopsies in intracranial tuberculomas

BACKGROUND

Stereotactic biopsies for diagnosing intracranial tuberculomas are often reported to be inconclusive, being confirmatory in only 28% of cases. We analyzed the role and diagnostic efficacy of stereotactic biopsies in the management of intracranial tuberculomas.

METHODS

Twenty patients diagnosed with intracranial tuberculomas based on neuroimaging procedures underwent computerized tomography (CT) guided stereotactic biopsies for histological confirmation. In 10 patients (Group A), biopsies were obtained from the center of the lesion; in the other 10 (Group B), biopsies were obtained from both the enhancing rim and the isodense center and examined separately. The tissues were processed for paraffin sections and hematoxylin eosin staining. In addition, in the first five patients a squash smear from a small portion of the biopsy was prepared, and the cytological features of the cells were examined. All the patients received antitubercular medication and CT scans were repeated 4 months posttreatment.

RESULTS

Histopathological features of the paraffin sections in 17 patients (Group A: 8, Group B: 9) were diagnostic of tuberculoma, whereas the other three revealed only chronic nonspecific inflammation. Based on the cytological features in squash smears, diagnosis could be made in one of five. In two, although the smear was not diagnostic, the histological section from the same specimen confirmed the tuberculous pathology. There was no procedural morbidity or mortality. One patient had a small asymptomatic hematoma at the biopsy site. Three patients died during the follow-up period, due to secondary complications of tuberculosis. Repeat CT scans during follow-up after antituberculous treatment confirmed the reduction in the size of the lesion in 15/17 patients.

CONCLUSION

The high positive yield of stereotactic biopsies in diagnosing tuberculomas argues for their inclusion in the management protocol for tuberculous mass lesions.

Benign triton tumor of the trigeminal nerve

Benign triton tumor (neuromuscular hamartoma) is a rare tumor of the peripheral nerves, comprising mature neural and striated muscle elements. We report the third case, according to the literature, of a benign triton tumor affecting the Vth cranial nerve in a 4-year-old male child. The tumor was seen to involve the mandibular division of the trigeminal nerve in the infratemporal fossa and extend intracranially by eroding the base of middle cranial fossa. The mass was totally excised. In the tumor, bundles of axons intermingling with fascicles of relatively mature skeletal muscle were found. This type of hamartomatous lesions of neuroectodermal-mesenchymal origin could have arisen as the result of incorporation of mesenchymal tissue into nerve sheaths during embryogenesis or aberrant differentiation of neuroectodermal component into mesenchymal elements.

Solitary olfactory groove schwannoma: case report with review of the literature

A 45-year-old man presented with headaches of 6 months' duration and generalized seizures in a cluster 2 days prior to admission. Examination revealed bilateral papilloedema and no focal deficits. CT scan showed an isodense enhancing mass lesion in the right frontobasal region with perilesional edema. Bifrontal craniotomy (with total excision of the tumor) revealed a tumor in the region of the right olfactory groove attached to the cribriform plate. Histopathological examination disclosed it to be a hyalinised schwannoma. Solitary schwannomas arising from the olfactory groove are extremely rare. Only six other cases have been reported so far. The presentation. CT scan findings and histogenesis of the tumor are discussed along with a review of the literature.

Infratentorial dysembryoplastic neuroepithelial tumor (DNT) associated with Arnold-Chiari malformation

Dysembryoplastic neuroepithelial tumor (DNT), a benign neoplasm, is now a well recognized clinicopathological entity. We report the second case of DNT in the cerebellum occurring in a 20-year-old male presenting with ataxia. He also had Arnold-Chiari malformation of the adult type. Histologically the tumor was a "simple" DNT having the specific "glioneuronal" element, namely oligodendrocyte-like cells (OLCs), mucoid change and floating neurons (Purkinje cells). A striking feature was the perpendicular arrangement of the neuropil columns extending from the pial surface to white matter similar to those seen in supratentorial examples. On immunstaining some of the OLCs were positive for synaptophysin and negative for glial fibrillary acidic protein (GFAP), glucocerebroside, tau and MAP-2. The neuropil was synaptophysin-positive and focally positive for MAP-2 and GFAP as well. The Purkinje cells were morphologically normal but malaligned and were positive for phosphorylated neurofilament suggesting secondary dysplastic changes. A transition of the lesion into relatively normal cerebellum preserving the folial architecture was observed. The histological and immunochemical features of the DNT in cerebellum suggests its possible origin from the pluripotential external granular layer.

Extensive cranial vault and skull base osteomyelitis complicating chronic mastoiditis : a case report

The authors report an unusual case of extensive osteomyelitis of cranial vault and skull base as a complication of chronic mastoiditis in a 19 year old girl. The diagnosis was confirmed by bone biopsy which revealed osteomyelitic changes and large bacterial colonies. The unusual features of this case is discussed along with review of relevant literature.

Intracranial plasma cell granuloma : a report of four cases

Intracranial plasma cell granulomas are a rare group of idiopathic inflammatory pseudotumours often mistaken for lymphoreticular malignancies and myeloproliferative disorders. The clinial and pathological findings in respect of four cases of intracranial plasma cell granuloma clinically diagnosed as meningioma and glioma are presented in this report. The range of microscopic features seen included a mixed cell population with predominance of plasma cells, absence of cellular atypia and mitosis, multinucleate giant cells, perivascular cuffing by inflammatory cells and emperipolesis. The major considerations in differential diagnosis of this lesion are discussed.

Neurocytoma/rhabdomyoma (myoneurocytoma) of the cerebellum

An unusual case of cerebellar neurocytoma with rhabdomyomatous differentiation in a 6-year-old boy is reported. Immunocytochemical and ultrastructural features of the tumour were studied. Abortive synapse formation, the presence of clear vesicles and synaptophysin immunoreactivity of the tumour cells indicated its intermediate neuronal differentiation, while the presence of myoblasts and myotubes and immunolabelling by desmin confirmed the rhabdomyomatous differentiation. In addition, the mesenchymal cells variably expressed neurofilament protein and glial fibrillary acidic protein, suggesting inductive interaction between the neuroectodermal and ectomesenchymal elements and persistence of the pleuripotential nature of the cells along the rhombic area of the brain stem.

Histopathological & immunohistochemical evaluation of ageing changes in normal human brain

As age related changes in the brain have not been systematically studied in the Indian population though there is an impression that they are less frequent, we studied 52 brains collected at autopsy from individuals above the age of 60 yr. The incidence of senile plaques (SPs) and neurofibrillary tangles (NFTs) together were found to increase with age from 21 per cent in the seventh decade to 33 per cent in the eighth decade and 54 per cent in the ninth decade, the increasing incidence of NFTs being statistically significant. The SPs were found both in the hippocampus and frontal cortex while NFTs were seen only in the hippocampus in non-demented aged individuals. In contrast, in the three cases of Alzheimer's disease (symbol: see text) AD studied, the NFTs and SPs were found in high density in both hippocampus and frontal cortex. By immunohistochemistry, various morphological forms of SPs were found to have beta amyloid protein consistently, while ubiquitin and phosphorylated neurofilament occurred variably. More number of SPs could be labelled by amyloid immunostaining than by conventional silver stains. The NFTs contained ubiquitin and phosphorylated neurofilament protein as the antigenic components, both in AD and normal ageing. The incidence of age related changes and their antigenic character in the limited sample studied from south India appears to be comparable to findings from the West. Multicentric studies on a large sample derived from different ethnic groups in India are needed to further evaluate these features.

Hemimegalencephaly--morphological and immunocytochemical study

Hemimegalencephaly (HME), a rare congenital abnormality characterized by unilateral enlargement of the cerebral hemisphere, is one of the less common causes of intractable seizures. We report a 6-month-old infant with uncontrolled seizures who was diagnosed to have a large mass lesion based on a CT scan. Postmortem examination revealed left-sided HME with pachygyria, widened cortex, indistinct grey-white junction, and distorted deep nuclear masses. Histological features included loss of cortical lamination, large atypical neurons with argyrophilic accumulations, ballooned cells, neuronal heterotopia, and astrocytosis with dystrophic calcification. The heterotopic neurons in the white matter were present in a radial pattern suggestive of aberrant neuronal migration. Several large neurons were dystrophic with cytoskeletal abnormalities like phosphorylated high molecular weight neurofilament and ubiquitin in the cytoplasm. However, typical neurofibrillary tangles with Congo red and tau positivity were not observed. Synaptophysin labelling was found to be decreased in the cortex, but some of the abnormal neurons had dense perisomatic label. The majority of the balloon cells were astrocytic in origin, being positive for glial fibrillary acidic protein and negative for the neuronal markers. Although the etiology of HME is not known, it provides an opportunity to study anomalous development of the brain and neuronal developmental abnormalities.

Colloid cyst xanthogranuloma of the third ventricle--a case report

A colloid xanthogranuloma of the third ventricle is described. Presenting features were symptoms of raised intracranial tensions and two episodes of seizures. The pathogenesis, clinical and radiological features, differential diagnosis and treatment of this rare benign lesion are briefly discussed.

Tuberculoma of the hypothalamic region as a rare case of hypopituitarism: a case report

In endemic regions, hypothalamic tuberculoma has to be kept in mind, and treatment instituted on suspicion. The disease may cause hypothalamopituitary insufficiency and inadequate response to surgical stress. A case of hypothalamic tuberculoma presenting with hypopituitarism is presented.

Disseminated Burkitt's lymphoma presenting as multiple cranial nerve palsies

A case of disseminated Burkitt's lymphoma with nervous system involvement in a HIV negative 35 year old lady is described. She primarily presented with multiple cranial nerve palsies. At autopsy, diffuse involvement of parenchymatous organs and lymphomatous meningitis with conspicuous sparing of gastrointestinal system was observed. In addition, there was an unusual feature of paraneoplastic demyelinating peripheral neuropathy. Incidentally, a large hydatid cyst was also seen in the left lobe in addition to the lymphomatous involvement of the liver.

Pathological lesions in HIV positive patients

Pathomorphological features of 10 HIV positive individuals studied at autopsy and biopsy are described. Nine patients had evidence of neuro-AIDS and eight of them succumbed to various opportunistic infections. One surviving patient underwent a diagnostic lymph node biopsy which revealed tuberculous lymphadenopathy. Cryptococcal meningitis was the commonest CNS opportunistic infection, seen in five cases, with disseminated systemic cryptococcosis in two. The other opportunistic infections included toxoplasma encephalitis in two, with acanthamoeba infection in one patient. Pulmonary tuberculosis was noted in three patients while other bacterial infections such as meningococcal meningitis, pseudomonas septicaemia were observed in three and pneumocystis carinii pneumonia in one. One seropositive individual was clinically asymptomatic but succumbed to a road traffic accident. The brain in this case showed features of HIV associated early leucoencephalopathy. Bacterial infections caused by organisms other than Mycobacterium tuberculosis associated with AIDS are often underdiagnosed and should be considered, especially in developing countries. In cases of cryptococcal and tuberculous meningitis or multiple parasitic infections, the patients should be screened for associated HIV infection.

Primary mycotic abscess of the brain caused by Fonsecaea pedrosoi. Case report

A case of cerebral abscess caused by Fonsecaea pedrosoi is reported in a nonimmunocompromised 15-year-old boy. In the absence of a primary cutaneous lesion, this fungus was considered to be a primary neuropathogen. The fungus was cultured and characterized from the abscess material obtained at surgery. Prompt therapy using amphotericin B and 5-flucytosine helped in the successful recovery of this patient.