The diagnosis of the often occurring "chalazion" usually puts no problems in diagnostic and therapeutical view. It must be considered, however, that already small particularities of the clinical findings point to other i.e. benign or even malignant processes. An analysis of a number of cases from 1969 to 1975 of the University Eye Clinic Münster showed in 21 out of 89 histologically examined tissue specimen another diagnosis. In 8 patients a malignant degeneration of tissue was histologically stated. The authors describe some cases, where during a longer period of time the malignant character of the disease was not diagnosed due to the misdiagnosed "chalazion".