Large cell anaplastic Ki-1+ non-Hodgkin's lymphoma vs. Hodgkin's disease in fine needle aspiration biopsy samples

Cytomorphologic analysis of large cell anaplastic Ki-1+ (Ki-1+ ALCL) and Hodgkin's disease (HD) in samples of fine needle aspiration biopsy (FNAB) was done to establish the morphologic differences between these two lymphomas.

In the period 1990-1994, FNAB of the lymph nodes and cytologic examinations were performed on 6,353 patients at the Department of Cytopathology, Institute of Oncology, Ljubljana. Of these, 160 patients had either a histologically or cytologically established diagnosis of HD or Ki-1+ ALCL. Cytomorphologic analysis of 28 cases (14 HD and 14 Ki-1+ ALCL) was done.

In 129/135 patients with HD, the cytologic diagnosis was confirmed by histology (96%), while in patients with Ki-1+ ALCL (8/11) this rate was 72%. The results of morphologic analysis were as follows. The proportion of blast cells exceeding 15 microns was > 18% in Ki-1+ ALCL and < 9% in HD. The number of lymphocytes and prolymphocytes was smaller in Ki-1+ ALCL than in HD. In Ki-1+ ALCL the cells could be arranged in groups. Immunologic reaction with CD30 in Ki-1+ ALCL, as compared to HD, was stronger and present in a larger number of cells. The rates in other cells were similar.

Profound knowledge of the cytomorphology of Ki-1+ ALCL and HD can help differentiate between these two lymphoma types; the number of large blast cells is the decisive factor.