[Juxtaglomerular cell tumors: report of two cases with genomic analysis]. / Tumeur à rénine du rein : à propos de deux cas, avec analyse génomique.

Juxtaglomerular-cell tumor (JGCT), first described in 1967, is a rare tumor of the kidney that derives from specialized smooth-muscle cells of the wall of the glomerular afferent arteriole. Less than 100 cases have been published, mainly as single-case reports or small series. JGCTs are considered benign, but the clinical follow-up has been short in most reported cases. Only one metastatic case has been reported to date, raising the question of tumors of uncertain malignant potential rather than clearly benign neoplasms. Genomic features have been studied in only two cases that showed gains on chromosome 10 as well as deletions on chromosomes 9, 11q and X. The present work studied the genomic characteristics of two additional cases of JGCT by CGH. Similarly to the two previously reported cases, these two tumors showed losses on chromosomes 9 and 11, suggesting recurrent chromosomal imbalances. In addition, one case showed gains and losses of entire chromosomes similar to a previous case studied by karyotyping. Such an aneuploid karyotype may reflect a potential for malignancy as previously reported. Thus, JGCT might be better considered as a tumor of uncertain malignant potential consequently requiring a prolonged follow-up. Future clinicopathologic and genomic studies of large retrospective and prospective series may help to better understand the biology of this fascinating entity.