Molecular profiling of renal cell carcinoma presenting as iris metastasis.

PURPOSE

To describe a case of iris metastasis as the initial presentation of clear cell renal cell carcinoma, and to discuss molecular profiling of both the metastasis and primary kidney tumor.

OBSERVATIONS

We report a patient with blurred vision who underwent ophthalmic examination and was found to have an iris mass, which was excised and diagnosed as a metastatic clear cell renal cell carcinoma by morphology and immunohistochemical analysis. As a result of the pathology findings, computed tomography imaging was performed, revealing a right kidney mass, which was also resected and shown to represent a high-grade carcinoma confined within the renal fascia without lymphovascular invasion. Molecular testing of the primary and metastatic tumors using a custom next-generation sequencing panel revealed similar mutational profiles but disclosed a promoter mutation in the primary neoplasm, not present in the metastasis, suggesting seeding of an early lower grade neoplastic cell clone within the iris.

CONCLUSIONS AND IMPORTANCE

This report illustrates how pathological examination of a small iris lesion led to the discovery of a previously unknown systemic malignancy at a resectable stage. Molecular genetic profiling revealed that even lower grade clones within a high-grade neoplasm have metastatic potential.