Orbital metastasis or idiopathic orbital pseudotumor? A case report from a patient previously diagnosed with primary breast cancer

Introduction: Cancer metastatic to the orbit may be difficult to distinguish from idiopathic orbital pseudotumor at clinical and radiological examination. This case report describes clinical, radiological features, differential diagnosis, and treatment options for orbital neoplasms of unknown origin. Presentation of case: A 63-year-old woman presented to our Unit because of orbital swelling, ocular pain, globe displacement, conjunctival chemosis, and progressive vision loss. The patient had been seen by an ophthalmologist at another hospital. The initial diagnosis was idiopathic orbital pseudotumor. Steroid therapy did not resolve clinical symptoms. Her medical history held decisive clues: ten years before this presentation she had been diagnosed with double primary breast cancer, invasive lobular breast carcinoma, and invasive ductal breast carcinoma. Orbital biopsy was performed for differential diagnosis. Discussion: Considering the rapid onset and severity of symptoms, the radiological features of the orbit, and the patient's medical history of breast cancer, orbital metastasis should have been the most likely diagnosis. Orbital biopsy was performed because of the history of multiple primary cancers and because metastatic origin had to be determined to define the best treatment strategy. Conclusion: Biopsy is necessary under specific circumstances in the diagnosis of orbital metastasis, especially when presentation is ambiguous and when differential diagnosis is challenging. A patient's medical history may hold vital clues to correct diagnosis.