An unusual cause of diplopia as the presenting sign of breast carcinoma

Enlargement of one or more EOMs with limitation of ocular motility is most frequently observed in thyroid associated orbitopathy and idiopathic inflammatory orbital pseudotumor; it may also be encountered in association with systemic disorders (vasculitis, granulomatous inflammation etc.). In a 47-year-old woman, presenting with a 4-months history of double vision, diplopia was the unique revealing sign of primary breast carcinoma. EOMs involvement with paraneoplastic process or metastases due to breast carcinoma is extremely rare. Differential diagnosis between those two potential sub-entities is discussed together with other causes for EOMs thickening.