Differ ential diagnosis of swelling in the region of orbita is relative broad. Exophthalmus may be caused by inborn defects, injuries, inflammations or tumors of orbita. The diagnosis and therapy of these conditions mostly requires a interdisciplinary approach with participation of the otolaryngologist. About 8% of all edemas affecting orbita is caused by mococoele of auxiliary nasal cavities. The otolaryngologist also participates in the solution of endocrine orbitopathies in cases, where a decompression operation is indicated. Although most diseases mentioned above become manifest by affecting one eye, endocrine orbitopathy causes. This contribution describes an unusual case of tumour disease of orbita. In view of bilateral exophthalmus, clinical course and character of the infiltrate during the examination by magnetic resonance and computer tomography, endocrine orbitopathy was taken into consideration. This diagnosis was also supported by sonographic finding of enlargedthyroid gland.Thecorrect diagnosis of bilateralmetastasis of breast cancer was only established on the basis of histological examination in the course of decompression operation. The differential diagnosis of swelling in the region of orbita and, particularly, the algorithm of individual diagnostic procedures are discussed. The imaging examinations and probatory excision of the tumor tissue under suitable surgical procedure should play a key role. In a unilateral non-inflammatory affection of orbita, primary or secondary tumor or metastasis into orbita should be considered. The bilateral affections may include endocrine orbitopathy, and inflammatory pseudotumor of orbita affects both eyes in 20%of cases.Another possibility of bilateral affection is the infiltration in lymphoproliferative diseases. Even metastases into orbita are not always affecting one eye - the survey of literature indicates bilateral disease in around 5% of cases. It is therefore necessary to point out the necessity of general examination of the patient, which in our patient revealed an advanced primary breast cancer, affecting both mammary glands and regional lymphatic nodes.

        Key words: ex ophthalmus, orbita metastases, breast cancer.