Septal granulomatous panniculitis in Sweet's syndrome. Report of two cases.

Two patients had Sweet's syndrome (acute febrile neutrophilic dermatosis) with subcutaneous lesions resembling erythema nodosum. In both, the erythema nodosum--like lesions histologically showed a septal granulomatous panniculitis with numerous Miescher's granulomas. This type of subcutaneous involvement in Sweet's syndrome should be differentiated from panniculitis caused by deep subcutaneous neutrophilic infiltration. Involvement of the panniculus in Sweet's syndrome may then occur in two different patterns: a septal granulomatous panniculitis, as in our two cases, or a neutrophilic lobular panniculitis, as has been previously reported.