OBJECTIVE:

To identify characteristic cytomorphologic and immunocytochemical features of anaplastic large cell lymphoma (ALCL).

STUDY DESIGN:

We reviewed all positive cytology cases from patients with histologically confirmed ALCL at the National Institutes of Health/National Cancer Institute for patient demographics, cytologic appearance and, when available, immunocytochemical staining pattern with markers for CD30, CD3, L26, CD15, leukocyte common antigen and epithelial membrane antigen (EMA).

RESULTS:

Twenty-one cases were reviewed from seven patients (four males and three females) aged 2-83 years; 2 were human immunodeficiency virus positive. Specimens included exfoliative (cerebrospinal fluid, pleural fluid) and aspirated material (lymph node, lung, soft tissue). Commonly noted morphologic features included a smear pattern of largely dispersed cells with focal aggregates; variability in cell size with smaller and larger multinucleated giant forms (average cell size 42 microm); eccentric, round to oval nuclei; prominent nucleoli; a "ropy" chromatin pattern; and deeply basophilic, variably vacuolated cytoplasm. Necrosis was frequent. A proteinaceous background was prominent in cellular samples. Lymphoglandular bodies and lymphoid tangles were not prominent. Of cases evaluated immunocytochemically, 100% were positive for CD30, and 75% showed EMA positivity. Expression of other markers was variable.

CONCLUSION:

ALCL has a distinct cytomorphologic appearance and immunocytochemical staining pattern such that a reliable diagnosis can be made on cytologic material.