Clinicopathological profile of Wilms' tumor.

The profile of renal tumors in children less than 15 years of age during the period 1991-1997 is presented. Among the 37 children with kidney tumors, 29 (78.4%) had Wilms' tumor. There was also a 20-year-old female with Wilms' tumor. The median age at presentation was 2.6 years (range 2.5 months to 20 years). 66.7% of the cases diagnosed were < or = 3 years and 90% were < or = 6 years. Five cases were under one year of age. The male to female ratio was 2:1. Twenty-two cases (73.3%) were triphasic and 7 (23.3%) were biphasic. Only one case was monophasic with blastemal component. Five cases (16.7%) showed nephrogenic rests in the uninvolved renal parenchyma and one case had nephroblastomatosis. The tumor was favorable in 26 cases (86.7%) and unfavorable in 4. Fourteen cases were in-patients while 16 were outside referrals. The pathological (10 cases whose specimens were sent from other centers) and clinicopathological (13 hospitalized patients) staging showed 10 cases (43.5%) with stage 1, 4 cases (17.4%) with stage 2, and 7 cases (30.4%) with stage 3. In two cases (8.7%), there was stage 4 disease. The length of the follow-up period in the 13 hospitalized patients ranged from 7 days to 5 years 5 months (median 14 months). There was one recurrence and one death after 2 years of diagnosis.

T cell rich B cell lymphoma (TCRBCL): study of sixteen cases with review of literature.

T cell rich B cell lymphoma (TCRBCL) is a recently described variant of diffuse non Hodgkin's lymphoma (NHL), the acronym of which has gained wide acceptance among hematopathologists in a relatively shorter period of time. The recognition of this entity requires immunohistochemical facilities especially on paraffin embedded tissues. TCRBCL is one of the many examples in the diagnostic anatomic pathology which emphasizes the need of immunocytochemistry and availability of this technique at least in referral laboratories. One of the differential diagnosis in this case includes lymphocyte predominance Hodgkin's disease (LPHD) which is the most favorable prognostic histologic subtype of Hodgkin's disease (HD) while TCRBCL is an aggressive B Cell NHL and should be treated as high grade large cell lymphoma. The other close differential includes peripheral T cell non-Hodgkin's lymphoma (PTCL). We reported sixteen (16) cases of TcRBCL diagnosed during a period of two and a half years (January 1995 to June 1997). HD and PTCL were the main differential diagnoses in most of these cases. The median age at diagnosis was 39 years and male to female ratio was equal. TCRBCL was nodal in location in 15 cases and a single case in extranodal site presenting as spinal tumor. The mean neoplastic B cell population was 12%, while that of reactive T cells was 82%. A significant polymorphous inflammatory cellular background was noted in 5 cases. Reed-Stenberg like cells were observed in 3 cases. Immunoglobulin light chain restriction studies were performed in fourteen cases and revealed lambda light chains in ten cases while in four cases kappa light chains were present.

Changing patterns and re-distribution of antigen in poorly differentiated carcinomas: its implications in tumour diagnosis.

The variability of expression of tumour-associated antigens via either antigenic heterogeneity or antigenic modulation presents a basic problem in immunohistochemical diagnosis of poorly/undifferentiated tumours. This work was designed to study antigenic expression on human resected epithelial tumours by a panel of most widely used antibodies (EMA, CEA, AUAI & Cytokeratin) in relation to tumour differentiation and polarization. It was observed that poorly differentiated carcinoma with loss of polarity show homogeneous membrane staining (with antibodies against EMA, CEA & AUAI) in contrast to either apical (luminal) or basolateral membrane staining in well differentiated counterparts. Biochemical studies have shown that apical and basolateral epithelial cell membrane domains have a characteristic set of glycoproteins. Tight junctions are essential for maintaining this functional polarization. It was concluded that structural and functional abnormalities of tight junctions in poorly differentiated carcinomas results in loss of polarity with progressive invasion of the cell surface by antigenic glycoprotein and resultant homogeneous individual cell antigenic expression in poorly differentiated carcinomas. This study demonstrates that antigenic expression on tumour cells is not static, but dynamic and heterogeneity of antigenic expression may well be due to biological factors such as spatial configuration of the lesion.