BACKGROUND Inconclusive cytomorphology often results due to failure to distinguish between adenocarcinoma cells from benign, reactive, atypical mesothelial cells in effusion specimens. To resolve such dilemmas, auxiliary techniques like immunohistochemistry were utilised to reach a definitive diagnosis for better treatment and management of patients. We wanted to compare cytodiagnosis achieved on cell block preparations with the cytodiagnosis on conventional smear and perform immunohistochemistry for epithelial membrane antigen (EMA), calretinin, desmin, vimentin and E-cadherin on cell block preparation of the fluids in cases of indistinguishable cytomorphology of adenocarcinoma and reactive, atypical, and benign mesothelial hyperplasia. METHODS The immunohistochemical markers namely EMA, calretinin, vimentin, desmin and Ecadherin were applied on cell blocks employing streptavidin-biotin method. Immunohistochemistry was interpreted by giving scores to the percentage of stained cells. RESULTS EMA and E-cadherin had 100 % sensitivity in diagnosing adenocarcinoma whereas calretinin, vimentin and desmin were 100 % sensitive in diagnosing reactive, atypical mesothelial carcinoma on the cell block preparations. CONCLUSIONS Immunocytochemistry of fluid should be carried out on the cell block preparation where cytological diagnosis on conventional smear and cell block fails to detect malignant cells in the preparation. KEY WORDS Cell Block, Adenocarcinoma, Mesothelial Cells, Immunohistochemistry, EMA, Calretinin, Vimentin, Desmin, E-Cadherin
Cytological diagnosis of metastatic alveolar rhabdomyosarcoma in the ascitic fluid: Report of a case highlighting the diagnostic difficulties