Cytologic Features of NK/T-Cell Lymphoma

OBJECTIVE: To describe the diagnostic cytologic features of NK/T-cell lymphoma. STUDY DESIGN: The cytologic features of 3 cases of natural killer cell (NK)/T-cell lymphoma were studied and correlated with histology. Immunohistochemistry for CD56, T-cell intracellular antigen (TIA-1) and EBV-encoded small nuclear RNAs (EBER) in situ hybridization was reviewed. RESULTS: The lymphomas have mixed-sized cells with eccentric, round to ovoid nuclei; 1 or 2 prominent nucleoli; and abundant, clear to pale, eosinophilic cytoplasm. Mitotic figures, necrotic debris and tingible body macrophages are common accompaniments. In fluid, the lymphoma cells appear more shrunken. A clot section of 1 case was positive for CD56, TIA-1 and EBER. CONCLUSION: Helpful cytologic features for the diagnosis of NK/T-cell lymphoma are described. Immunohistochemistry for CD56, TIA-1 and EBER in situ hybridization are very helpful adjuncts for the diagnosis.