Background: Ki-1-positive anaplastic large cell lymphoma (Ki-1 ALCL), one of the more recently described pleomorphic types of lymphoma, affects mostly children and adolescents and is sometimes mistaken for carcinoma or sarcoma.
Cases: Two cases of Ki-1 ALCL were diagnosed on cytology. One patient presented with generalized lymph-adenopathy and involvement of the skin and subcutis, while the other was admitted with pneumonia and multiple subcutaneous masses in the chest wall. Fine needle aspiration cytology smears in both cases showed dissociated cells with abundant, lightly basophilic, vacuolated cytoplasm; oval, round or lobulated nuclei; and binucleate, trinucleate and multinucleate cells with a wreathlike arrangement of nuclei. Most of the tumor cells expressed immunocytologic reactivity to CD 30, and a cytologic diagnosis of Ki-1 ALCL was made. Tru-cut biopsy of the chest wall tumor in case 2 and review of lymph node biopsy done one year previously in case 1 permitted a cytohistologic correlation.
Conclusion: Knowledge of the distinctive cytomorphologic features of Ki-1 ALCL combined with the clinical setting should enable its distinction from other pleomorphic neoplasms in most cases, while in others it should go a long way toward narrowing the cytologic differential diagnosis.