Difficult Diagnosis of Colon Adenocarcinoma Metastasis to Retina: A Case Report and Literature Review

Intraocular metastatic tumors have been increasingly reported in the recent past. Unlike choroidal metastasis, metastasis to retina is very rare and so far has been reported in very few case reports only. A 56 year-old male who presented with a history of adenocarcinoma of the cecum and underwent lap colectomy for the primary cecal tumor, received adjuvant chemotherapy for a year after surgery and decided to stop. He was also diagnosed with metastasis to liver and lung at this time. He presented with left eye pain, pressure and decreased vision suspicious for retinal metastasis from cecal primary lesion, 2 years after initial diagnosis. A mass of 5 x 10 mm was found on ophthalmoscopic examination and on ultrasound of the eye, in spite of normal results of MRI of the orbit. Palliative radiation therapy of the left eye resulted in decreased eye pressure and improved vision. As retinal metastasis carries a poorer prognosis due to higher risk of spread to central nervous system, the diagnosis of retinal metastasis in case of gastrointestinal cancers patients who present with vision changes should be made urgently. These patients should be thoroughly investigated with a synergistic approach of opthalmoscopic examination, ultrasound of the eye along with other imaging modalities like MRI of the orbit and just not MRI of orbit. Immediate action in the form of surgical or radiation treatments of the metastatic tumors of the eye should be instituted early on for a better prognosis.