The development of a Ki-1-positive large cell non-Hodgkin's lymphoma in pagetoid reticulosis

: A case of the disseminated variant of pagetoid reticulosis is described which progressed after many years of disease to a large cell anaplastic (Ki-1) lymphoma of T-cell type. The lymphoma cells showed abnormal cellular DNA and a high proliferative rate, as revealed by immunophenotypic examination and single-cell DNA measurements. The cells were positive for activation associated antigens and expressed a T-helper/inducer phenotype. A similar phenotype was expressed by the neoplastic cells in the co-existing lesions of pagetoid reticulosis. These findings support the view that pagetoid reticulosis is a variant of the cutaneous T-cell lymphomas which originates from activated lymphoid cells and which may on occasion progress to a potentionally more aggressive lymphoid malignancy.