Intravascular histiocytosis presenting with extensive vulvar necrosis

Intravascular histiocytosis (IVH) is a rare reactive cutaneous lesion of unknown pathogenesis. Most cases are reported in association with rheumatoid arthritis, and cutaneous eruptions typically occur near swollen joints. The skin changes have included erythematous and violaceous macules, papules, plaques and indurated patches with a livedo-like pattern of erythema. We report the first case of IVH presenting with florid vulvar necrosis in an 87-year-old patient without a history of rheumatoid arthritis. Physical examination revealed an edematous, exudative and diffusely necrotic vulva with erythema surrounding the areas of necrosis, extending out to the thighs. The debrided skin revealed an extensively necrotic epidermis and multiple clusters of markedly dilated blood vessels within the dermis. These vessels contained fibrin thrombi admixed with numerous CD68⁺ and CD163⁺ histiocytes. Her skin changes improved significantly after surgical debridement and treatment with antibiotics. Interestingly, our patient was also found to have a lupus anticoagulant with elevated anticardiolipin antibodies. This is the first report of IVH possibly related to a thrombogenic diathesis associated with a hypercoagulable state. A diagnosis of IVH is important and may necessitate further clinical evaluation to exclude the possibility of co-existent systemic disease.