The presence of coexistent disseminated granuloma annulare (GA) and Hodgkin's disease (HD) is rare, with only six reported patients to date. We describe a patient with HD who had limited GA 2 years before the diagnosis of HD; widespread GA appeared after first-line treatment and heralded disease relapse. GA lesions showed hypermetabolic images on positron emission tomography, an interesting finding of unknown significance. We suggest a new pathophysiological mechanism for this association, i.e. that the reactive T-lymphocyte population in HD may contribute to granuloma formation through the secretion of cytokines and the subsequent upregulation of certain metalloproteinases. Diffuse cutaneous GA should raise the possibility of underlying systemic lymphoma or HD.