Summary. Lethal midline granuloma is a rare clinical syndrome. In clinical practice the destructive process of the facial midline may appear as a symptom of various infective, malignant or autoimmune diseases. A physician must have a good knowl- edge of the problem in order to make a rational approach to diagnosis. The present paper discusses the case of a 34-yearold patient with destructive changes of midline, nose, perforating of palatal cleft and destruction of bone structure of nose, maxillary and ethmoid sinus. For histopathologic diagnosis of T-lymphoma it was necessary to make immunohistological study of the biopsy specimen. Irradiation therapy with total dose of 5600 cGy showed an extremely good therapeutic result. Three years after irradiation therapy the patient is still in a remission.