Fine-needle aspiration cytology of peripheral T-cell lymphoma. A cytologic, immunologic, and cytometric study

The diagnosis of peripheral T-cell lymphoma (PTCL) is difficult. This entity can be misdiagnosed as Hodgkin's disease or a reactive process such as nonnecrotizing granulomatous lymphadenitis or it can present a problem in lymphoma classification. Fine-needle aspirates from 13 patients with histologically proven PTCL were evaluated by cytology, immunochemistry, and flow cytometry. Of the 13 patients with PTCL, initial cytologic diagnoses were atypical lymphocytic infiltrate (2), mixed-cell lymphoma (6), mixed-cell lymphoma with associated histiocytes (2), large cell lymphoma (2), and small cell lymphoma (1). Surface marker studies were performed on cytospin preparations. Antibodies against cytotoxic-suppressor (Leu-2a) and helper-inducer (Leu-3a,b) antigens were used in 11 cases. Ten lymphomas demonstrated helper phenotype and one showed phenotypic heterogeneity in two different sites. The most prominent cytologic features of PTCL were a variable combination of small, intermediate, and large lymphoid cells with irregular nuclei, presence of epithelioid histiocytes, and atypical mononuclear cells. Flow cytometry studies showed a diploid stem line with intermediate proliferative activity (mean S-phase of 6.7%) in most cases, despite the clinical aggressiveness of this neoplasm.