Co-existence of chronic renal failure, renal clear cell carcinoma, and Blau syndrome.

Blau syndrome is a rare, multisystem, autosomal-dominant, and granulomatous disorder caused by susceptibility variants in the NOD2 gene. We describe here a 14-year-old girl with Blau syndrome with incidentally diagnosed renal carcinoma. The index case presented with growth retardation and recurrent symmetric arthritis. Her clinical symptoms included bilateral cataract due to recurrent uveitis, camptodactyly, and persistent erythematous rash with ichthyosis. Her two sisters and her mother were affected with combinations of these conditions-symmetric polyarthritis, uveitis, and skin involvement-suggesting an autosomal dominant trait. The index case developed a chronic renal insufficiency, and an abdominal computerized tomography scan revealed a 2.5-cm mass in the left kidney. The histopathological examination showed renal clear cell carcinoma, chronic tubulointerstitial nephritis,and giant cell granulomas in both the tumor and nonneoplastic renal tissue. Granulomatous inflammation was observed in the skin biopsy specimen. The patient was diagnosed with Blau syndrome based on her family history, uveitis, granulomatous inflammation proved by skin biopsy, and polyarthritis. Sequencing of the NOD2 gene showed a heterozygous p.R334Q mutation in all affected family members. To the best of our knowledge, this is the first reported case of a patient with Blau syndrome accompanied by chronic renal failure and renal carcinoma.