For the evaluation of neoplastic orbital lesions an interdisciplinary concept is crucial and includes modern imaging techniques as well as rhinosurgical approaches to the orbit. During a 14-year period 6 primary malignant orbital lymphomas and 9 cases of orbital pseudotumors were managed at our department. In most of the cases an exophthalmus with painful swelling of the eyelids, diplopia and a loss of vision were the clinical symptoms. Imaging using CT or MRI revealed homogeneous tissue formations that could not be clearly demarcated from adjacent orbital structures. By a rhinosurgical approach a biopsy was performed of each lesion without surgical complications. Following diagnosis the localized malignant lymphomas of the orbit were irradiated. In one patient systemic spread of tumor required multi-drug chemotherapy. Two patients died as the result of the sequleae of disseminated plasmocytomas. Patients with orbital pseudotumors were treated with systemic steroids. Two patients were also irradiated. No malignant transformation of any orbital pseudotumor was observed in this series. Our experiences show that careful histological evaluation of lymphoid orbital masses is necessary for correct diagnosis, especially since this has great impact on treatment and prognosis. Depending on the localization of a lesion medial orbitotomy by a rhinosurgical approach has proven to be a safe method for performing a biopsy or extirpating tumor.