OBJECTIVE Granulomatous orbital inflammation may occur as an isolated condition of unknown origin. These idiopathic granulomatous lesions are believed to belong to the orbital pseudotumor group by some authors, whereas others consider them sarcoidosis limited to the orbit. The aim of this study is to define the clinicotherapeutic aspects of these lesions. METHODS The records of all patients with diagnosis of orbital pseudotumor and orbital sarcoidosis from the Orbital Center Amsterdam in the period between 1976 and 1994 were reviewed to define those with idiopathic granulomatous orbital inflammation. The authors studied the clinicotherapeutic aspects and histopathology of idiopathic granulomatous orbital inflammation by analysis of their own series and the literature. RESULTS Their study group encompassed seven patients with idiopathic granulomatous orbital inflammation. The mean follow-up was 9.5 years (range, 3.5-16.0 years). All had unilateral orbital presentation, with localization in the lacrimal gland in three patients. The lesions clinically presented with signs of mass effect or inflammation or both and were treated successfully with surgery, systemic corticosteroids, a combination of surgery and systemic corticosteroids, or systemic corticosteroids followed by irradiation. Histopathologic analysis showed a spectrum of granulomatous inflammation, admixed with nongranulomatous inflammation and fibrosis. There have been 30 similar cases described in the literature with comparable clinicotherapeutic characteristics. CONCLUSIONS Based on this study and the literature, it appears that idiopathic granulomatous orbital inflammation is more related to orbital pseudotumor than to orbital sarcoidosis.