Adult Pleomorphic Juxtaglomerular Cell Tumor.

A 40-year-old male with chronic hypertension since his teens presented to the emergency department following a motor vehicle collision. Computed tomography scan demonstrated an incidental 1.8-cm renal mass. Partial nephrectomy revealed a vascular tumor with predominantly monomorphic epithelioid cells arranged in sheets and trabeculae with foci of nuclear pleomorphism. Tumor cells were positive for vimentin, CD34, and c-KIT. Juxtaglomerular cell tumor is a rare, benign neoplasm typically found in young adults. Pleomorphism is uncommon and, in combination with older age at diagnosis, can lead to an inaccurate malignant diagnosis. Immunohistochemistry and clinical history helps in correctly diagnosing this benign entity.