CD-30(Ki-1)-positive anaplastic large cell lymphoma in a pleural effusion. A case report with diagnosis by cytomorphologic and immunocytochemical studies.

BACKGROUND: Reports on cytodiagnosis of Ki-1-positive anaplastic large cell lymphoma (ALCL) are rare. This report describes one such case diagnosed by cytologic examination of a pleural effusion and confirmed by immunocytochemistry. CASE: An 87-year-old male presented with breathlessness, fever and a cough. Computed tomographic scan of the thorax showed a small, right, pleura-based nodule with infiltration of the immediate surroundings in addition to a massive, right-sided pleural effusion. Cytologic examination of pleural fluid revealed a heterogeneous population of cells comprising small mature lymphocytes, and numerous medium and large atypical lymphoid cells having frequent nuclear irregularity. Occasional very large cells resembling Reed-Sternberg cells or multinucleated cells with a horseshoe or wreathlike arrangement of nuclei (doughnut cells) were also present. Cytomorphology was suggestive of Ki-1 anaplastic large cell lymphoma (ALCL). Immunocytochemistry revealed intense positivity for CD-30, positivity for LCA and EMA in a variable number of cells and a negative result for cytokeratin except for occasional cells. CONCLUSION: Cytologic examination of pleural fluid can serve as a useful tool for the initial diagnosis of Ki-1-positive ALCL.