Abstract Lymphocytic thrombophilic arteritis is a recently described entity, histopathologically characterized by lymphocytic vasculitis that affects the arterioles of the dermo-hypodermic junction, associated with deposition of fibrin and a luminal fibrin ring. A 49-year-old female patient presented with achromic maculae and a well-defined ulcer on the medial aspect of the left lower limb. The biopsy showed intense inflammatory infiltrate in the papillary dermis with a predominance of lymphocytes, and medium-caliber vessels surrounded by mononuclear infiltrates in the deep reticular dermis. Masson's trichrome staining showed intense destruction of the muscle layer of the vascular wall and a fibrin ring. Good clinical response was attained with azathioprine. The authors believe that the ulceration might be another clinical presentation or represent an atypical progression of this condition.