[396] Hematolymphoid Malignancies in Serous Effusion Cytology: Cytomorphology, Ancillary Studies, and Diagnostic Pitfalls

D Marks-Jones, W Khalbuss. University of Pittsburgh Medical Center, Pittsburgh, PA

Background: Detection of lymphomas and leukemias in serous effusion cytology is difficult. The current study aims to review the cytomorphology, diagnostic pitfalls, and ancillary studies of serous effusion cytology specimens which were reported as diagnostic of malignant lymphoma or leukemia.
Design: All serous effusion cytology specimens over a 3.5 year period with a diagnosis of a hematolymphoid malignancy were retrospectively reviewed. The cytological material, ancillary studies, and available histological follow-up were analyzed.
Results: Out of the 3892 serous effusion cases, 93 (2.4%) cases were diagnostic of a hematolymphoid malignancy. This included 72 pleural, 19 ascitic, and 2 pericardial fluids. The final diagnoses included: diffuse large B cell lymphoma (n=18); chronic lymphocytic leukemia (n=15); Non-Hodgkin's B-cell lymphoma, not otherwise specified (n=14); plasma cell myeloma (n=13); follicular lymphoma (n=7); acute lymphoblastic leukemia (n=7), acute myelocytic leukemia (n=5); marginal zone lymphoma (n=3), mantle cell lymphoma (n=3), T-cell lymphoma (n=3), Burkitt lymphoma (n=2), Hodgkin's lymphoma (n=1), primary effusion lymphoma (n=1), and post-transplant lymphoproliferative disorder (n=1). Eighty-four patients (90%) had a previous diagnosis of lymphoma or leukemia, while the remaining 9 (10%) had no history of malignancy. The differential diagnoses in these cases included: reactive lymphocytosis, small cell carcinoma, small round blue cell tumors, poorly differentiated carcinoma, reactive mesothelial cells, and potential mimics of Reed-Sternberg cells. The most helpful cytomorphological features were the presence of non-cohesive, small to intermediate size atypical cells with a scant to moderate amount of basophilic cytoplasm, frequent nuclear irregularities, and apoptosis (best seen in cell block preparations). Ancillary studies were utilized in 61 cases, including flow cytometry in 49 cases, immunocytochemistry in 27 cases, and FISH in 4 cases.
Conclusions: The cytological diagnosis of leukemia and lymphoma in serous effusions is difficult due to the cytologic mimics and pitfalls. Exfoliative cytology is a valuable method for diagnosing hematolymphoid malignancies. Cell block preparations and fresh samples for flow cytometry or FISH studies provide material for ancillary studies which can help to sub-classify these entities.
Category: Cytopathology

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 65, Monday Morning