Reliability and validity of Rhabdomayosarcoma histological diagnosis

Rhabdomyosarcomas (RMS) are soft tissue tumours of skeletal differentiation that are relatively common. They present a diagnostic challenge in histopathology laboratories where immunohistochemistry (IHC) staining is not routine. They tend to mimic many other tumours morphologically like small round blue cell tumour. Objectives: The aim of this study was to determine the reliability and validity of the morphological diagnosis of rhabdomyosarcoma using haematoxylin and eosin (H & E) with IHC as the reference standard in the Department of Pathology. This was a laboratory-based cross-sectional study to assess the reliability and validity of the morphological diagnosis of haematoxylin and eosin. All cases of rhabdomyosarcoma diagnosed using H&E during the study period from January 2000 to December 2012 in the Department of Pathology were sampled. The sample size in this study was 200 samples. Haematoxylin and eosin method has high sensitivity but low specificity with fairly high diagnostic accuracy. Therefore confirmation of all RMS cases diagnosed by H and E using IHC is necessary, as haematoxylin and eosin method has a high false positive rate.