Preliminary Cytomorphologic Diagnosis of Hematolymphoid Malignancies in Effusions: A Cyto-histo Correlation with Lessons on Restraint.

Background: Effusions as part of hematologic neoplasms are rare and as a primary presentation, rarer. In standalone laboratories of developing countries, resorting to techniques such as flow cytometry or immunohisto/cytochemistry may not be possible. A near definitive diagnosis on cytomorphology would, therefore, be an ideal beginning. To that end, we compiled our cases of primary hematolymphoid effusions, devising reproducible reporting categories and looked at their concordance with the final histopathology. Subjects and Methods: Fifty-four cases of primary hematolymphoid effusions over 10 years with cytology-histopathology correlation were chosen. Post morphology assessment, the cases were organized into six categories: suspicious of hematolymphoid malignancy, non-Hodgkin lymphoma-high-grade (NHL-HG), low-grade NHL (NHL-LG), Burkitt lymphoma, acute leukemias, and plasma cell dyscrasias. Discordance with histology was assigned as major and minor based mainly on therapeutic implications. Results: Concordance was seen in a good number (81.5%) of cases. The NHL-HG and NHL-LG categories contributed to 33.3% each of major discordance. Tuberculosis and epithelial malignancies comprised the bulk of the major discordance. Overdiagnosis of a high-grade lymphoma for a histologically proven low-grade follicular lymphoma was the only case with minor discordance. Conclusion: The cytologic categories used are not foolproof for hematologic neoplasms but have a fairly good concordance. A scanty abnormal population should always be viewed with suspicion and definitive labels should be avoided. While morphologic examination is fraught with danger, a good assessment directs the judicious selection of ancillary methods, and hence cannot be supplanted.