Distal cutaneous necrosis, an unusual etiology: hyperhomocysteinemia

Introduction. Homocysteine is a sulfur amino acid occurring in methionine i ntermediary metabolism. It was recently shown to be a vascular risk factor even without high serum levels. Case report. A 29-year-old woman had painful plantar nodules and necrosis o f the fifth toe on the right foot with cyanosis of the forefoot. The histol ogy examination of a nodule biopsy gave the diagnosis of subcutaneous throm bophlebitis. Vascular explorations disclosed advanced-stage arteriopathy of the leg. The methionine loading test was abnormal and search for the heter ozygous form of cystathionine beta was positive. Discussion. Different diagnoses could be possible for cases associating an inflammatory venous disease and stage IV arteritis. Latent hyperhomocystein emia was diagnosed in this case on the basis of the methionine loading test and identification of the heterozygous form of cystathionine beta. Patient s with latent hyperhomocysteinemia have an increased risk of both thrombosi s and arteritis. Our case emphasizes the importance of searching for hyperh omocysteinemia in patients with early arterial and/or venous thomboembolism , either as repeated episodes or occurring in an unusual territory.