Juxtaglomerular cell tumor of kidney with CD34 and CD117 immunoreactivity: Report of 5 cases

Context.-Juxtaglomerular cell tumor is a rare renal neoplasm. Renin immunohistochemistry and electron microscopic documentation of rhomboid crystals are the primary methods of diagnosing this benign tumor. Objectives.-In this retrospective study, we evaluated the morphologic, immunohistochemical, and ultrastructural features of 5 cases of juxtaglomerular cell tumor to determine the effectiveness of CD34 and CD117 immunohistochemistry for the diagnosis of this tumor. Design.-We reviewed 5 cases with clinical, histologic, immunohistochemical, and ultrastructural aspects. Results.-Three women and 2 men with a mean age of 37.8 years (range, 16-60 years) were included in this study. All patients presented with severe hypertension. All tumors were well circumscribed and ranged from 1.5 cm to 8.5 cm (mean, 4.4 cm). On light microscopic examination, we found solid sheets and nests of tumor cells with oval-to-round nuclei and eosinophilic cytoplasm. Low-power microscopic examination disclosed a hemangiopericytic vascular pattern. Immunohistochemistry results were as follows: vimentin (positive), renin (weakly positive), smooth muscle actin (focal immunoreactivity), and cytokeratin (negative). All 5 tumors were immunoreactive for CD34 and CD117. Electron microscopy revealed rhomboid crystals in the cytoplasm. Postoperatively, 4 patients were normotensive and 1 patient experienced persistent mild hypertension. Conclusions.-Our findings indicate that immunohistochemistry for CD34 and CD117 are effective at diagnosing juxtaglomeruiar cell tumor. Juxtaglomerular cell tumor should be considered in the diagnosis of any renal tumors with epithelioid cells and negative initial cytokeratin immunohistochemistry.