Signet ring adenocarcinoma of the colon presenting as an orbital metastasis

A 67-year-old woman was referred after MRI imaging revealed an infiltrative, diffusely enhancing left intraconal lesion. Ophthalmic examination revealed a left proptosis, resistance to globe retropulsion, and restriction of extraocular motility in all fields of gaze. The result of a biopsy via an orbitotomy was consistent with signet ring adenocarcinoma. PET scanning was significant for lytic vertebral and rib lesions and activity within the cecum. Colonoscopy confirmed the diagnosis of stage 4 colonic adenocarcinoma. Although colon carcinoma presenting as an extraconal orbital metastasis has been reported, this is the first reported case of signet ring adenocarcinoma of the colon presenting as an intraconal orbital metastasis without eyelid involvement. Orbital metastatic disease from known primary malignancies is uncommon and in particular from carcinomas arising from the gastrointestinal tract. When metastatic orbital disease is found, studies have reported that as high as 42 % of these patients have an undiagnosed primary malignancy. This allows orbital surgery to play a role detecting as yet undiagnosed carcinomas.

Level of Evidence: Level V, diagnostic study.