Impact of Chemotherapy and Radiotherapy on Iris Metastases: A Case Report

Iris metastases are a rare initial presentation of a systemic malignancy, managed with chemotherapy and radiotherapy in most cases. These cases provide visual documentation of iris metastasis resolution following chemotherapy and radiotherapy and illustrate potential adverse effects associated with treatment response, including intraocular pressure variations and development of iris synechiae.

Two cases presented to metropolitan hospitals with ocular pain, which on ophthalmic review, revealed the presence of vascularised iris lesions. One case had a history of lung adenocarcinoma, on maintenance chemotherapy in addition to palliative radiotherapy to other metastatic deposits (case 1), whilst the other had no known history of malignancy (case 2). Case 2 required extensive investigations to obtain a histopathological diagnosis and stage the malignancy, after which he received chemotherapy followed by radiotherapy. In contrast, case 1 proceeded with immediate management with radiotherapy, followed by chemotherapy. Following the commencement of either treatment modality, tumour response was noted, with corresponding elevations in intraocular pressure, which was managed with topical glaucoma eye drops in addition to systemic acetazolamide. Both cases experienced complete remission of their iris metastases, though case 1 had extensive iris synechiae and case 2 passed away due to a rapid decline in their systemic malignancy.

Our case offers a unique visual insight into the impact of both systemic chemotherapy and localised radiotherapy on uncommon iris metastases, with sequential images taken at each stage of treatment. We underscore the importance of continual monitoring of the intraocular pressure during treatment, as tumour response was associated with elevated intraocular pressures in both of these cases. We hypothesise that this may be due to a combination of tumour liquefaction and hyphaema blocking trabecular meshwork outflow. Finally, despite treatment of the iris metastasis, patients may be left with residual iris synechiae, requiring additional surgical intervention to manage the intraocular pressure.