Membranocystic changes in the panniculitis of dermatomyositis.

Clinically apparent panniculitis is rare in dermatomyositis. The common histopathological findings are infiltration of lymphocytes, epithelioid cells and plasma cells in the fat lobules, along with varying degrees of fat degeneration and fibrosis. We report a 65-year-old woman with dermatomyositis who developed panniculitis with a characteristic histological change known as a membranocystic lesion. Although this change has been observed in various diseases affecting the subcutaneous fat tissue, it has rarely been reported in dermatomyositis. Dermatomyositis should be included in the diseases showing a membranocystic lesion.