Iris metastasis: clues to the primary through immunohistochemistry

A woman in her late 40s was referred to our tertiary care ocular oncology specialty clinic with the complaint of an elevated mass on the iris of the left eye of about 6 weeks' duration. The vision in the affected eye was normal and there were no associated ocular or systemic complaints. The left eye had a solitary amelanotic nodule with intrinsic vessels on the temporal iris. An excision biopsy with histopathology revealed features of metastatic adenocarcinoma. Immunohistochemistry workup pointed towards a primary in the lungs. A high-resolution chest CT scan showed an upper lobe mass in the right lung. A whole-body positron emission tomography-CT (PET-CT) scan showed this lesion to be metabolically active. Additionally, it showed active mediastinal and supraclavicular lymph nodes, and active lesions in the brain parenchyma. The patient received chemo- and radiation therapy with palliative intent at a general oncology facility.