We present a unique case of a woman with multiple painful dermal lesions localized to the left upper quadrant of the body. Histological investigation revealed microvascular thrombosis with capillary-wall proliferation. Further investigation revealed a very high anticardiolipin IgG titre and a left subclavian stenosis, presumably providing the reduced blood flow and relative hypoxia to allow microthromboses to occur in the presence of a thrombophilic tendency. Similar clinical and histological features have been reported in patients with the antiphospholipid syndrome and cases of reactive angioendotheliomatosis (RAE). This case represents a unique variant of RAE.