Cytological diagnosis of lymphoma in serous effusions.

A consecutive series is presented of 100 cases of malignant lymphoma in which a correlation could be made between the histological findings and the cytology of pleural or peritoneal fluid or both. Using the Kiel classification, 80 cases could be given a histological label, while 20 remain unclassified. In those cases in which lymphoma cells were identifiable in the serous fluid, their morphology was studied and was found in general to correlate well with the cell-type expected from the histology. It is not claimed that the type of lymphoma can be reliably diagnosed from the cytology of pleural or peritoneal fluid, but an opinion can be provided as to the grade (high or low), and in some cases it is also possible to give an indication of the cell-type involved.