Purpose: Granulomatous slack skin (GSS) is a rare cutaneous disorder characterized clinically by the evolution of circumscribed erythematous lax skin masses, especially in the body folds, and histologically by a granulomatous T-cell infiltrate and loss of elastic fibers. GSS is often associated with preceding or subsequent lymphoproliferative malignancies, especially mycosis fungoides (MF) and Hodgkin’s disease (HD). No effective treatment is known yet. Whether this entity is a benign disorder, a peculiar host reaction to a malignant lymphoma, a precursor of malignant lymphoma or an indolent cutaneous T-cell lymphoma (CTCL) in itself is still a matter of debate. Patients and Methods: The results of the patients with GSS from the Netherlands are compared with the cases reported in the world literature. Results: A female patient had had GSS for 8 years without developing a secondary malignancy. In a second female patient with a histologically confirmed diagnosis of MF, GSS developed 18 years later in the axillary and inguinal folds which had previously been affected by plaque-stage MF lesions. A third male patient with a 6-year history of erythematosquamous skin disease diagnosed as CTCL developed GSS. Moreover, granuloma formation was also found in a facial basal cell carcinoma, in a cervical lymph node and the spleen. Clonal rearrangements of the T-cell receptor β genes were found in the 2 female patients; the male patient could not be tested. Conclusion: GSS is a rare clinicopathological entity. Only 34 patients have been described so far. The development of GSS within plaque MF lesions has not been reported before. Our third case developed very extensive skin lesions and showed a strong propensity to develop granulomas as compared to cases reported before. The presence of a clonal T-cell population was demonstrated in all cases tested. Our cases support the idea that GSS is a very rare and rather indolent type of CTCL. Apparently, the disease is associated with a peculiar immune response, characterized by granuloma formation and disappearance of elastic fibers resulting in the lax skin. The relationship between GSS and other preexisting or subsequent lymphoproliferative diseases (diagnosed in approximately 50% of the cases) warrants a life-long follow-up.