[Pleural effusion revealing Horton's disease].

Pulmonary involvement is rare in Horton's disease. Only few cases have been reported presenting as interstitial infiltration, pulmonary artery vasculitis, pulmonary nodules and granulome formation. Pleural effusion was rarely reported. A 65-year-old male patient presented with a right pleural effusion. Horton's disease was evoked in the presence of cephalgias, an ocular involvement and general signs. Temporal artery biopsy showed giant cell arteritis. After negative etiologic work up, pleural effusion was attributed to Horton's disease. Outcome was favourable with systemic corticosteroid therapy. Pleural involvment in Horton's disease is rare and characterized the absence of specific biological and histological findings. However, pleural effusion may be a presenting manifestation of Horton's disease.