Cytomorphologic Differentiation of Hodgkin’s Lymphoma and Ki-1+ Anaplastic Large Cell Lymphoma in Fine Needle Aspirates

OBJECTIVE: To cytomorphologically differentiate Hodgkin's lymphoma (HL) from Ki-1+ anaplastic large cell lymphoma (ALCL) in fine needle aspirates. STUDY DESIGN: We blindly reviewed 63 fine needle aspiration (FNA) smears from histologically and immunophenotypically proven cases of ALCL (n=15) and HL (n=48). The smears were reviewed for the following criteria: (1) estimated percentages of abnormal cells, (2) pattern of the smears (polymorphous vs. dimorphous), and (3) presence or absence of multilobated cells. RESULTS: All cases were phenotyped by immunohistochemistry for CD3, CD15, CD20, CD30 and CD45, with flow cytometric immunophenotpyping in 41 cases. Flow cytometric phenotyping was not successful in any of the cases. The smears were polymorphous in all 15 cases of ALCL and in 1 case of HL (2%). The percentage of abnormal cells ranged from 10% to 90% in cases of ALCL (median, 30%) whereas it ranged from 1% to 25% in HL (median 3%; P=.0003). Three cases of HL showed abnormal cells constituting ≥20% of the smears. They were all grade 2 disease. Multilobated cells were identified in 14 of the 15 cases of ALCL (93%) and in 3 of the 48 cases of HL (6.25%) P =.0008). CONCLUSION: Our findings indicate that the differentiation of ALCL from HL can be achieved in FNA smears through identification of abnormal cells representing > 30% of the population, a spectrum of abnormal cells and the presence of multilobated nuclei. Rare cases of grade 2 HL may be difficult to differentiate from ALCL.