Abstract
A 69-year-old woman sustained progressive proptosis for 2 months. The patient had undergone surgery for resection of colon cancer 10 years prior, which was considered to have been completely cured 5 years prior. She was also aware of a hard mass in her left breast, but it had been left untreated. Furthermore, she experienced back pain for a month. Blood examination revealed an elevated level of serum carcinoembryonic antigen, at 17.4 ng/mL (< 5). Computed tomography (CT) revealed a tumor occupying the superolateral part of the right orbit, with intratumoral calcifications and destructive changes in the lateral orbital wall. On magnetic resonance imaging, it appeared as a heterogeneously enhancing, extraconal tumor, 44 mm × 31 mm in maximal dimension, extending into the middle fossa and the adjacent subcutaneous region. Fluorodeoxyglucose positron emission tomography/CT revealed abnormal accumulation in the left breast, T12 vertebra, liver, and lung, in addition to the orbital tumor. The patient underwent total tumor resection through a lateral orbitotomy. Histological examination of the tumor was highly suggestive of a metastatic colon cancer. Late metastasis should be assumed as a differential diagnosis that can be determined only through histological verification.