BACKGROUND Granulomatous slack skin is a very rare subtype of T-cell cutaneous lymphoma, characterized by the slow development of cutaneous sagging, especially on flexural areas. Its behavior is indolent and the treatment, in the majority of cases, disappointing. MAIN OBSERVATION We report a 54-year-old black patient with granulomatous slack skin, who at the beginning of the investigation showed intense xeroderma and generalized lymph node enlargement. The diagnosis was established based on histopathologic findings long before the disease's characteristic clinical presentation appeared. CONCLUSIONS During the twelve years of follow-up, the clinical manifestation evolved to marked skin looseness, most predominant in flexural regions, illustrating the clinical hallmark of granulomatous slack skin, long after first histological abnormalities were observed.