Introduction Involvement of body fluids by lymphoreticular malignancies (LRM) is rare and often associated with poor prognosis and decreased overall survival. The present study was conducted to analyze the characteristic cytomorphologic, flow cytometric and immunocytochemical features of LRMs in serous effusions. Materials and methods This was a three-year retrospective study. A total of 218 effusion samples, reported as involved by lymphoreticular malignancies, on cytology, were reviewed. All the cases wherein the cytological diagnosis was confirmed by flow cytometric (FCM) and/or immunocytochemical (ICC) studies were retrieved and studied in detail. FCM and/or ICC were performed in a total of 51/218(23.4%) samples, including 30 pleural (58.8%), 18 peritoneal (35.3%), and 3 pericardial fluid (5.9%) samples. Results The cytomorphologic diagnoses included infiltration by non-Hodgkin lymphoma (NHL;n = 27), infiltration by LRM (n = 19), infiltration by chronic lymphocytic leukemia (CLL;n = 2), Hodgkin's lymphoma (HL;n = 1) and suggestive of infiltration by LRM (n = 2). FCM and/or ICC confirmed the diagnoses as infiltration by T-cell lymphoblastic lymphoma in 18; mature B-cell NHL in 10; Burkitt lymphoma in 7; diffuse large B-cell lymphoma in 4; follicular lymphoma, T- cell NHL and CLL in 2 samples each and hairy cell leukemia, plasmablastic lymphoma and HL in 1 sample each. 94.1% concordance was noted between the initial and final cytologic diagnosis. Conclusions Involvement of body fluids and effusions by LRMs, though rare, carries an immense prognostic significance and hence the prompt detection is crucial. Detection of these malignancies by cytologic examination of effusions is challenging yet potentially useful and the least invasive method available to establish an early diagnosis.
