RESUMEN
We report 39 years old man with the history of chronic sinusitis and rhinitis. After tooth extraction he gradually developed unilateral proptosis with ophtalmoplegia and visual loss caused by retroorbital mass which was related to destruction of the adjacent orbital walls, sinuses and base of the skull. During the following month the progressing lung nodules with mediastinal and hilar lymphadenopathy, macular skin lesions, renal insufficiency with proteinuria and anaemia appeared. The diagnosis of Wegener's Granulomatosis (WG) was formed on the base of clinical features and result of pathologic examination of surgical specimen from the paranasal sinuses. The progressive course under the standard immunosuppressive therapy required reevaluation of histologic slides, which resulted with the diagnosis of diffuse large B-cell lymphoma confirmed by the immunohistochemical staining. Administration of CHOP regimen resulted in spectacular regression of all of lesions.