[Pagetoid reticulosis of the Ketron-Goodman type]

The case of a 79-year-old woman with widespread pagetoid reticulosis (Ketron-Goodman type) is presented. The nature of the epidermal cellular infiltrate in pagetoid reticulosis of the Ketron-Goodman type was examined by immunohistochemical methods and by electron microscopy. On ultrastructural examination the infiltrating cells proved to be medium-sized and large Sézary-type and blastoid cells. Immunohistochemically, the epidermal infiltrate was composed of approximately 80% immature T cells (OKT 16) and 30% proliferating cells (Ki 67). Mature T cells (CD 5) were found to account for only 15-30% of all cells in the infiltrate. These results suggest that pagetoid reticulosis (Ketron-Goodman type) is a malignant T-cell lymphoma, which is characterized, in addition to the epidermotropic behavior common to all T-cell lymphomas, by innidiation and in-situ spread within the epidermis.