Juxtaglomerular cell tumor: Clinicopathologic evaluation in a large series emphasizing its broad histologic spectrum

The juxtaglomerular cell tumor (JCT) is a rare renal tumor. We re-evaluated the clinicopathologic features of 21 JCTs to summarize their variable morphologies. Immunohistochemical, fluorescent in situ hybridization and periodic acid-Schiff stains were routinely performed, and four JCT cases were detected via transmission electron microscopy. The 21 JCTs involved five males and 16 females, ranging in age from 19 years to 69 years (mean, 36.9 years; median, 34 years). The tumors were composed of large, small, or spindle cells with a round, oval or polygonal shape, arranged in various growth patterns. Both necrosis (1/21) and mitosis (2/21, with 1/50HFP, 8/50HFP) was rarely appreciated. All cases were immunoreactive for renin and CD34 (21/21), and few were positive for α-SMA (13/21;11/21, focally; 2/21, diffusely,), CD117 (9/21, focally) and synaptophysin (3/21, focally). Ultrastructurally, all four cases exhibited secretory granules in varying sizes in the cytoplasm, two of which exhibited cellular junctions. Almost all cases (20/21) had a favorable prognosis, but one succumbed due to bone and hepatic metastases, which corresponds to malignant JCT. Our study demonstrates that JCTs may have atypical clinical presentations and variable histologic appearances. A familiarity with these features may contribute to a correct diagnosis.