Volume 21, Number 1Case ReviewSymptomatic Rosai-Dorfman Disease Presenting as Isolated Bilateral Perinephric InfiltrationBryant Van LeeuwenDaniel J KmetzDennis BentleyThis case explores a rare initial presentation of Rosai-Dorfman disease isolated to the peri-renal space. Also described as sinus histiocytosis with massive lymphadenopathy, Rosai-Dorfman disease is non-neoplastic and most often presents with massive cervical lymphadenopathy, but the disease can affect any organ system. Not often considered by those in the urology community or found in urology journals, this report reviews a clinical presentation of Rosai-Dorfman disease affecting bilateral kidneys and the fundamental histopathology needed for its diagnosis. [Rev Urol. 2019;21(1):41–44] © 2019 MedReviews®, LLCRosai-Dorfman diseaseSinus histiocytosis with massive lymphadenopathy