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Biomedical subjects

D Govender

Publications and source records attributed to D Govender.

36 records · Page 2Linked to original sources
PubMed1999

Intracranial mass lesions in HIV-positive patients--the KwaZulu/Natal experience. Neuroscience AIDS Research Group.

BACKGROUND: Neurological disease heralds the development of AIDS in 10-20% of HIV-seropositive individuals. In over half of these cases the presentation will be that of an intracranial mass lesion (IML). In developed countries toxoplasmosis is the most frequent cause of IML in a positive patient, followed by primary central nervous system lymphoma. Less common causes include tuberculomas, cryptococcomas, abscesses and gummas. As a result of these observations, the algorithm adopted in developed countries calls for initial empirical treatment for toxoplasmosis. Biopsy of the IML is only considered if there is no response to treatment after 10-14 days. Whether such an algorithm would be applicable to the local population is unknown. OBJECTIVE: We undertook a prospective study to determine the type and frequency of IML in local HIV-seropositive patients. A secondary objective, based on the findings, was to develop a local algorithm of management. PATIENTS AND METHODS: Over a 17-month period HIV-seropositive individuals with an IML were entered into the study. Biopsy or aspiration of the lesion was performed either stereotactically or free-hand. Tissue obtained was processed for routine and special histological studies. RESULTS: In the 38 cases where tissue was obtained, the most frequent cause of the IML was toxoplasmosis followed by encephalitis of obscure origin', brain abscess and tuberculoma/mycobacterial infection. CONCLUSION: This study demonstrated that the spectrum of IML seen locally was similar to that in developed countries. The management protocol used elsewhere was therefore adopted for local patients.

Adolescent↗
PubMed1998

p53 protein expression in nephroblastomas: a predictor of poor prognosis.

Alteration of the tumour-suppressor gene p53 is the commonest genetic change encountered in human malignant tumours. A study was undertaken to ascertain the prognostic value of p53 immunoexpression in nephroblastomas. A series of 93 consecutive cases was analysed. Archival formalin-fixed, paraffin wax-embedded tissue sections were stained with monoclonal anti-p53 antibody (DO-7, Dako) using a peroxidase-labelled streptavidin biotin kit. Five of seven tumours (71.4%) with unfavourable histology, but only 3 of 86 favourable histology tumours, showed 'high' p53 immunoexpression (P < 0.001). p53 expression in unfavourable histology tumours was present in both anaplastic and non-anaplastic components. Moreover, there was uniform staining of blastema, epithelium and stroma in unfavourable histology tumours. No statistical difference in p53 expression was found between patients who had received and those who had not received preoperative chemotherapy (P = 0.678). Similarly, no statistical difference was found in the groups of patients who were disease free, who had residual/recurrent disease or who had died (P = 0.238). The mean survival period for patients with tumours that had 'low' and 'high' expressions was 24.8 months and 12.6 months respectively (P = 0.0003). In conclusion, p53 immunoexpression in nephroblastomas was found to be an important determinant of poor prognosis as it identifies those patients with a shorter survival period and also those with unfavourable histology tumours. It may also be of practical value to the practising pathologist by identifying those tumours that require careful assessment for the presence of anaplasia.

Adolescent↗
PubMed1998

Primary hepatic osteosarcoma: case report and literature review.

We describe a primary osteosarcoma of the liver in a 72 year old man. The man was symptomatic and had suffered abdominal pain and distension for four months before he died. At autopsy a large tumor of the liver with direct extension into adjacent structures was found. There was no evidence of primary tumor or primary bone lesion at any other site. Histologically, the tumor comprised malignant cells producing abundant osteoid arranged in a lace-like pattern. Smaller chondroblastic and fibroblastic components were also present. These findings were in keeping with a diagnosis of primary hepatic osteosarcoma.

Aged↗
PubMed1998

Primary myxoid liposarcoma with rhabdomyoblastic differentiation.

We report a unique case of primary myxoid liposarcoma of the floor of the mouth, in which well-differentiated rhabdomyoblasts were present. The tumor was incompletely excised. The patient is free of recurrence or metastasis following a course of radiotherapy. Heterologous components found in a liposarcoma include leiomyosarcoma, rhabdomyosarcoma, chondrosarcoma, osteosarcoma, and angiosarcoma. These elements have been described mainly in dedifferentiated liposarcomas situated in the retroperitoneum. To our knowledge, there has been only one report of a liposarcoma with rhabdomyosarcomatous differentiation occurring in the absence of a dedifferentiated component. The clinical implications of the presence of heterologous components without dedifferentiation are unclear.

Adult↗
PubMed1997

Lung carcinomas composed of rhabdoid cells.

Rhabdoid tumours form a distinctive morphological entity that is associated with aggressive biological behaviour. They have been described in several sites and tumour types. This paper presents three new cases of rhabdoid lung cancers. Lung cancers were analysed for the presence of cells with the rhabdoid phenotype: eccentric vesicular nuclei and abundant eosinophilic cytoplasm. Cells displaying this morphology were then subjected to immunohistochemistry and electron microscopy. The relevant clinical data on these cases were then accessed. Three cases conforming to the morphological, immunophenotypic and ultrastructural characteristics of rhabdoid cells were identified. Two of the cases were associated with foci of adenocarcinoma and the remaining case was a large cell neuroendocrine carcinoma. Two of the cases showed rapid clinical courses with the patients dying of disease within 6 months. Lung tumours with a rhabdoid phenotype are uncommon but are noteworthy because of their aggressive behaviour and, hence, poor prognosis.

Adult↗
PubMed1997

Large cell neuroendocrine carcinoma of the thymus.

AIM: We highlight the occurrence of an unusual neuroendocrine tumour, a large cell neuroendocrine carcinoma, arising from the thymus. CASE DETAILS: A 68-year-old man with a history of cigarette smoking had a large mediastinal tumour arising from the thymus removed. Two years later the tumour recurred; it was debulked surgically but the patient died 2 months later: Histological examination of both tumour specimens revealed a tumour with an endocrine pattern, composed of large pleomorphic cells with large nuclei and prominent nucleoli. The mitotic count ranged from 19 to 26 per 10 high-power fields and large tracks of coagulative tumour necrosis were present. The tumour cells were strongly positive for neuron-specific enolase (NSE), chromogranin, CAM5.2 and AE1/3, with cytoplasmic dot-like accentuation for the latter three markers. The tumour fulfilled the criteria for a diagnosis of large cell neuroendocrine carcinoma. CONCLUSIONS: Large cell neuroendocrine carcinoma should be distinguished from atypical carcinoid and small cell carcinoma. It is a distinctive neuroendocrine malignancy with a prognosis between that of atypical carcinoid and small cell carcinoma, and needs to be treated aggressively.

Aged↗
PubMed1997

Mucosal prolapse changes in Hirschsprung's disease.

The aim of this study was to ascertain the incidence of mucosal prolapse changes in Hirschsprung's disease. Twenty-three random, consecutive resection specimens for this condition were analysed for the histological features of prolapse. Eight cases showed histological evidence suggesting mucosal prolapse at the junction between ganglionic and aganglionic bowel. Thickening and splaying of the muscularis mucosae with extension into the lamina propria, and the presence of metaplastic or hyperplastic tubules with goblet cell and cryptal hypertrophy were the dominant histological features found in the eight cases. In addition, an increase in elastic fibres in the lamina propria and diamond-shaped glands were seen to varying degrees in all eight cases. Mucosal prolapse was more prominent in the older patients and is, therefore, related to duration of symptoms. Differential pressures in ganglionic and aganglionic segments of bowel, together with faecal stream and straining are likely to be of pathogenetic significance.

Child↗
PubMed1997

Inflammatory pseudotumor of the breast.

Inflammatory pseudotumors (IP) have come to the forefront in recent times with this characteristic lesion being described in several sites. The multiplicity of sites of occurrence is matched by the plethora of names given to this condition. It has been rejoiced under the rubric of plasma cell granuloma, xanthomatous pseudotumor, xanthogranuloma, inflammatory myofibroblastic tumor/lesion and inflammatory fibromyxoid tumor, to name but some. This paper presents three cases of IP occurring in the breast and highlights the histological features in this unusual site.

Adolescent↗
PubMed1997

Granuloma inguinale (donovanosis): an unusual cause of otitis media and mastoiditis in children.

Granuloma inguinale (donovanosis) is seen predominantly in adults (it rarely occurs in children) and mainly affects genital skin and mucosa. Infection occurs at other skin and mucosal sites, and hematogenous dissemination to bone also has been described. The infection responds dramatically to appropriate antibiotic treatment. We present two cases of granuloma inguinale occurring in children (8 months and 5 months of age) causing mastoiditis and external ear discharges. A temporal lobe abscess also developed in the 8-month-old child. Subsequent computed tomography scans showed marked improvement in the brain lesion after treatment. The second child had a polypoid mass in the middle ear that on biopsy showed the features of granuloma inguinale. The mother of this child had biopsy-proven granuloma inguinale of the uterine cervix. These cases indicate that granuloma inguinale can be transmitted during vaginal delivery, and careful cleansing of neonates born to infected mothers is recommended.

Anti-Bacterial Agents↗
PubMed1997

Inflammatory pseudotumour and Rosai-Dorfman disease of soft tissue: a histological continuum?

A lesion of the chest wall in a 34 year old woman, which had a combination of histological and immunophenotypic features of inflammatory pseudotumor and Rosai-Dorfman disease of soft tissue, is described. There was considerable overlap in the pathogenesis, histology and immunophenotype of these two lesions. The similarities between these two lesions suggest that there is a temporal sequence and a histological continuum with early histiocyte-rich and late fibroblast- and myofibroblast-rich lesions. Alternatively, the morphological and immunophenotypic features could be because of aberrant cytokine expression in an inflammatory pseudotumour, resulting in transformation of histiocytes to resemble those seen in Rosai-Dorfman disease.

Adult↗
PubMed1997

CD31 (JC70) expression in plasma cells: an immunohistochemical analysis of reactive and neoplastic plasma cells.

AIMS: To investigate the immunohistochemical expression of CD31 (JC70) in normal and neoplastic plasma cells. METHODS: Plasma cells in bone marrow biopsies and extramedullary locations were examined. All extramedullary biopsies were formalin fixed and paraffin embedded. The bone marrow biopsies were fixed in formal acetic acid and embedded in paraffin wax. Twenty multiple myelomas (12 bone marrow and eight extramedullary deposits), 10 extramedullary plasmacytomas, and 30 biopsies with reactive plasma cells (10 bone marrow, 20 extramedullary biopsies) were stained with anti-CD31 (JC70) using the streptavidin-biotin detection system with diaminobenzidine as a chromogen. Antigen retrieval in bone marrow biopsies was achieved by pressure cooking. In all other biopsies, antigen retrieval was achieved by microwave pretreatment. RESULTS: All 20 extramedullary cases with reactive plasma cells showed intense membrane staining. Focal staining was detected in reactive plasma cells in bone marrow biopsies. Five of 10 plasmacytomas showed membrane staining. None of the cases of multiple myeloma, either medullary or extramedullary, showed any immunoreactivity for CD31. CONCLUSIONS: CD31, a member of the immunoglobulin supergene family of cell adhesion molecules, is strongly expressed in extramedullary reactive plasma cells, focally in bone marrow reactive plasma cells, and occasionally in extramedullary plasmacytomas.

Cohort Studies↗
PubMed1995

Advances in protein-based three-dimensional optical memories.

An oriented bacteriorhodopsin cube is optimized as a potential three-dimensional optical memory medium. Write/read capability is demonstrated by using the photovoltaic signal induced by two-photon absorption. Our results demonstrate that a two-photon induced photovoltage can he detected in a three-dimensional Bacteriorhodopsin (BR) cube as large as 1.6 x 1.6 x 1.6 cm3. The read/write speed, signal to noise ratio, and the laser damage threshold for the protein-based three-dimensional optical memory is examined.

Bacteriorhodopsins↗
PubMed1990

Adenomatous hyperplasia of the rete testis in the undescended testis.

Multiple foci of micronodular or tubulopapillary structures were noted in the rete testis of 13 cases of undescended testes. These structures were lined by low columnar to cuboidal epithelium, showed back-to-back crowding, and were supported by a thin lamina propria. These changes, referred to as adenomatous hyperplasia of the rete testis, appear to be a frequent finding in the undescended testis. An age-matched control group did not show any of these features.

Adolescent↗
PubMedDate not supplied

Clear cell (glycogen-rich) rhabdomyosarcoma presenting as cervical lymphadenopathy.

A 15-year-old patient is described who presented with cervical lymphadenopathy. A lymph node biopsy confirmed a metastatic neoplasm composed of islands and aggregates of round to polygonal-shaped cells with surrounding hyalinised fibrous stroma. The tumour cells contained a clear glycogen-rich cytoplasm and stained for desmin, muscle-specific actin and sarcomeric actin. Electron microscopy revealed paranuclear thick and thin filaments. These findings confirm striated muscle differentiation and a diagnosis of glycogen-rich clear cell rhabdomyosarcoma. The tumour recurred in a cervical lymph node after 2 years. This is yet another tumour that must be considered in the differential diagnosis of clear cell tumours of the head and neck region.

Actin Cytoskeleton↗
PubMedDate not supplied

Perineurioma: an unusual cause of an external auditory canal polyp.

A 33-year-old woman presented with pruritus of the right ear and on examination was found to have 1 x 1 cm polypoid lesion in the external auditory canal. This was removed and histological examination revealed a well-circumscribed spindle cell lesion arranged in fascicles and whorls. Immunohistochemistry showed the tumor to be EMA-positive but S-100-, desmin-, actin-, and cytokeratin-negative. Ultrastructural examination confirmed perineurial cell origin. There are several lesions in which perineurial cells are present, but a true perineurioma is composed exclusively of perineurial cells. It has characteristic morphological, immunohistochemical and ultrastructural features that help separate it from other nerve and neuroectodermal lesions.

Adult↗