A comparative microphotometric analysis of adult T-cell leukemia/lymphoma (ATLL) in the skin and mycosis fungoides (MF).

In the skin lesions of 16 adult T-cell leukemia/lymphoma (ATLL) and 13 mycosis fungoides (MF), morphological features of cutaneous infiltrates and their cell kinetics were evaluated through microphotometry of nuclear DNA content and nuclear size on Feulgen-stained sections. Lymphomas comprising some giant cells with irregular-shaped nuclei were found only in ATLL and these cells revealed aneuploid high DNA values. In contrast, neoplastic cells with pale cytoplasm in the Giemsa stain were seen more frequently in MF (69.5%) than in ATLL (12.5%). Patterns of the cutaneous infiltration according to skin microenvironments such as perivascular areas, dermal papillae, and periadnexal areas, were similar in the both entities. In the perivascular areas a mixed proliferation of lymphoma cells and non-neoplastic lymphocytes was conspicuous. The lymphoma cells were determined by high DNA values and large nuclear sizes. But the ratio of lymphoma cells to non-neoplastic cells in the infiltrates in the perivascular areas was higher in ATLL than in MF. In the dermal papillae and around the skin appendages, lymphoma cells predominated. Lymphoma cells which formed a plaque or tumor in the dermis contained many actively proliferating cells having higher DNA values and larger nuclear sizes than the lymphoma cells without tumor formation. One case of ATLL intermediate cell type showed, however, few proliferating cells inspite of tumor formation, suggesting a pooling or a long life-span in the skin.