A case of cytophagic histiocytic panniculitis associated with exertional rhabdomyolysis

An 18-year-old man who suffered from panniculitis involving the entire left lower limb after exertional rhabdomyolysis is reported. A high fever (> 39 degreesC) and leukocytosis (> 20 000/muL) persisted for 1 week, and his ge neral status deteriorated rapidly into pre-disseminated intravascular coagu lation, complicated by pleural effusion and prolonged clotting time. His co ndition was dramatically improved by steroid pulse therapy and he has remai ned in good health for the 20 months since discharge. Histologic examinatio n of subcutaneous tissue from the swollen left lower limb revealed pleomorp hic small, medium or large lymphocytes, macrophages and neutrophils infiltr ating the edematous subcutaneous adipose tissue in a lobular panniculitis-l ike pattern. The majority of inflammatory cells were T lymphocytes, with eq ual proportions of CD4+ and CD8+ cells. As polymerase chain reaction did no t show bands suggesting T cell receptor gamma gene rearrangement, the proli feration of T lymphocytes was considered to be polyclonal. The T lymphocyte s also expressed Fas ligand, suggesting the involvement of Fas-mediated cyt otoxicity. This case may represent a new category of cytophagic histiocytic panniculitis induced by exertional rhabdomyolysis.