Immunohistochemical evaluation of small round cell tumors of childhood

This study was done to evaluate the pediatric undifferentiated small round cell tumors with immunohistochemical staining.

The present study included consecutive cases of small round cell tumors which were diagnosed in children (< 15 years) in the section of Histopathology at the Aga Khan University Hospital, Karachi during the period of two years.

The group of undifferentiated small round cell tumors were evaluated immunohistochemically by using a panel of antibodies on sections from routinely processed, formalin fixed, paraffin embedded tissue blocks.

The category of undifferentiated small round cell tumors included rhabdomyosarcoma (23.2%), primitive neuroectodermal tumor (17.9%), non-Hodgkin's lymphoma (16.1%), neuroblastoma (14.2%), Ewing's sarcoma (10.7%) in order of frequency. Osteosarcoma (Small cell variant), retinoblastoma and medulloblastoma comprised 1.8% each. In seven cases (12.5%), the immunohistochemical analysis was inconclusive.

Immunohistochemistry is a very valuable diagnostic tool which helps in distinguishing the undifferentiated tumors especially small round cell tumors. The immunohistochemical staining needs to be performed routinely for undifferentiated tumors in diagnostic histopathology.