Prognostic significance of cytomorphology in the cutaneous T-cell lymphomas

In this retrospective study, the degree of differentiation of atypical lymphoid cells was assessed in pretreatment cutaneous biopsy specimens from 248 patients with cutaneous T-cell lymphomas (mycosis fungoides and Sézary syndrome) and the findings were correlated with the subsequent therapeutic results. Overall, patients with a predominance of cells with hyperchromatic nuclei (well-differentiated lymphoid cells) in cutaneous infiltrates responded better to treatment with improved survival rates than patients with infiltrates composed predominantly of cells with pale vascular nuclei (poorly differentiated lymphoid cells). Infiltrates with a predominance of poorly differentiated lymphoid cells were observed primarily in patients with advanced (tumor) stages of disease. However, comparison of the therapeutic results achieved for the two cytomorphologic patterns in patients at comparable stages of advanced disease did not reveal significant differences, indicating that the presence of poorly differentiated cells in large proportions does not have additional prognostic implications beyond those obtained from usual staging procedures. We speculate that the atypical cells with large, pale vesicular nuclei found in lesions of cutaneous T-cell lymphoma are not a more malignant cell population but rather evolve from more hyperchromatic cellular forms, perhaps a byproduct of malignant dedifferentiation.