[Extratemporal Horton's disease: diagnosis using subclavian biopsy. 4 cases]

A histological diagnosis of Horton's disease was made in 4 patients with lesions of the axillary-subclavian arteries by biopsy of these vessels. Unilateral biopsy of the temporal artery, performed initially in 2 of these patients, during surgery in one and immediately after surgery in another, had been negative in 3 cases and insufficient for a diagnosis in 1 case. For temporal biopsy to be valuable, the arterial fragment resected must be long enough and serial histological sections must be performed to avoid false-negative results. It is only when these conditions are fulfilled that negative results may be considered. Horton's disease of the axillary-subclavian arteries is relatively frequent, and histological studies of these vessels have already been used to assert the diagnosis in case of negative or non-performed temporal biopsy, whether or not the arteriographic findings were suggestive of the disease. The indications for subclavian biopsy remain to be determined. It can be carried out for diagnostic purposes in case of clinically atypical suspected Horton's disease revealed by axillary-subclavian lesions and negative temporal biopsy, particularly when revascularization proves necessary.