A comparison of the histopathologic features of Shulman's syndrome (diffuse fasciitis with eosinophilia) and the fasciitis associated with the eosinophilia-myalgia syndrome is presented. The study population consisted of eight biopsy specimens of seven patients with Shulman's syndrome and 11 specimens from 10 patients with eosinophilia-myalgia syndrome. Both groups exhibited inflammatory changes in the subcutaneous fat, septa, and fascia; cutaneous changes were more prominent in cases of eosinophilia-myalgia syndrome. Eosinophils and plasma cells were not consistently present in either condition; mast cells and factor XIIIa-positive cells were consistently present in the inflammatory infiltrates. Although there was overlap in the histopathologic findings, Shulman's syndrome tends to involve the subcutis alone and the eosinophilia-myalgia syndrome tends to be a pancutaneous-subcutaneous process.