Wells' syndrome or eosinophilic cellulitis is an uncommon cutaneous disorder characterized by recurrent erythematous and edematous plaques that often resemble acute cellulitis. The characteristic microscopic findings are diffuse dermal eosinophilia with marked edema, and flame figures consisting of amorphous or granular eosinophilic material around collagen bundles of the dermis. Etiology and pathogenesis are unknown, but the disease has been found to be associated with infections, arthropod bites, drug administration, surgery and hematologic disorders. We report the case of a 55-year-old man with pancreatic carcinoma who was presented with an asymptomatic erythematous to brownish subcutaneous nodule on the left buttock of several days' duration. A biopsy specimen taken from the erythematous to brownish nodule showed many flame figures and diffuse infiltration of eosinophils in the dermis and subcutaneous fat tissue. The rapid resolution of the skin lesion with chemotherapy of the pancreatic carcinoma supports a relationship between the two conditions. (Korean J Dermatol 1999;37(6): 785-789)