Abstract

OBJECTIVE:

To investigate the clinical characteristics, morphologic and immunohistochemical features, diagnosis, differential diagnosis, histogenesis and prognosis of renal juxtaglomerular cell tumor (JGCT).

METHODS:

Light microscopic observation; immunohistochemical assay of CK8, E-cadherin/CK7, CD10, Vim, Actin, CD34, S100, HMB45, CD31, Chr, Syn and CD117, EM; and follow-up were done on all 4 surgically treated JGCT patients.

RESULTS:

All 4 JGCT were observed in young adult with clinically uncontrolled severe hypertension. Grossly, the tumor was encapsulated and small in size. Microscopically, the tumor cells grew in sheets predominantly, but papillary and onion-like pattern could also be seen. The stroma contained prominent vasculature that consisted of numerous thin-wall vessels clustering around thick-walled vessels. Tumor cells were rather small, polygonal, with slightly eosinophilic cytoplasm and ill-defined cell border. Nuclei were uniform in size but nuclear atypia and mitosis could be seen. Numerous mast cells were scattered among the tumor cells, and tubules were identified in 3 of 4 cases with positive expression of distal tubule marker of E-cadherin/CK7. Tumor cells positively expressed Vim, Actin, calponin, and CD34. All cases presented ultrastructural features of distinct rhomboid-shaped crystal. There was no recurrence or metastasis but hypertension persisted in three during follow-up (mean 37 months) for all 4 JGCT patients.

CONCLUSION:

JGCT, originating from the juxtaglomerular cell, has a distinct benign entity, and it is typically found in young adults with severe hypertension. It has a unique morphology and ultrastructure features and positive immunoreactivity to Vim, Actin, calponin and CD34.

Abstract

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 ofjuxtaglomerular 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 juxtaglomerular cell tumor.Juxtaglomerular cell tumor should be considered in the diagnosis of any renal tumors with epithelioid cells and negative initial cytokeratin immunohistochemistry.