The spectrum of histopathologic findings in cutaneous lesions in patients with Still disease.

OBJECTIVES Still disease is a rare disorder characterized by seronegative arthralgias/arthritis, spiking fever, and either an evanescent salmon-colored rash or persistent papules and plaques. METHODS We describe the clinical and biopsy findings in 10 patients with the evanescent rash of Still disease. RESULTS Fourteen biopsy specimens were studied from seven women and three men with a mean age of 44.4 years. The skin lesions were typically erythematous macules, papules, or plaques with a median duration of 5 weeks. All patients had systemic symptoms, including fever and arthralgias. The infiltrate was predominantly lymphocytic in six biopsy specimens, approximately equal lymphocytic and neutrophilic in four biopsy specimens, and predominantly (although never exclusively) neutrophilic in four biopsy specimens. Other findings included focal vacuolar interface changes, neutrophilic eccrine hidradenitis, epidermal neutrophils, dermal mucin, and acanthosis associated with numerous upper epidermal dyskeratotic cells. CONCLUSIONS It is important to be aware of the broad histologic spectrum that may be encountered in Still disease and to consider Still disease in the differential diagnosis of neutrophil-rich, lymphocyte-rich, and mixed inflammatory dermatoses. While the histologic findings seen in biopsy specimens of the evanescent rash are nonspecific, a distinctive variant also exists characterized by prominent epidermal apoptosis, especially involving the upper layers.