Pagetoid reticulosis (PR) is a rare form of cutaneous T-cell lymphoma [Mod Pathol 2000;13:502–510]. Two variants of the disease are described: the localized type Woringer-Kolopp disease (WKD) and the disseminated type Ketron-Goodman disease (KGD). KGD may have disseminated lesions, high rate of recurrence and a guarded prognosis [Mod Pathol 2000;13:502–510]. In patients with KGD, therefore, long-term observation is necessary. Disappearance of cutaneous lesions does not mean resolution of the disease [J Am Acad Dermatol 2002;47:183–186]. Herein we report the case of an 84-year-old man with erythematous patches of the trunk and the upper and lower extremities in whom the diagnosis of KGD was made. We describe this case for the rarity of this pathology and for the good response to therapy (IFN).