About 75% of cutaneous lymphomas belong to the group of T-cell lymphomas. Mycosis fungoides is the most common entity in this group. Granulomatous slack skin is a rare form of cutaneous T-cell lymphoma closely related to mycosis fungoides. We present here a patient with areas of lax skin for several years who developed a generalized erythroderma with associated immunoactivation and a deterioration in his general condition. This report discusses clinically and histologically the differential diagnoses, namely granulomatous slack skin and granulomatous mycosis fungoides, and suggests that these 2 disorders are only variants in the broad spectrum of a single disease.