Chromosome abnormalities in juxtaglomerular cell tumors

Abstract

Juxtaglomerular cell tumors (JGCT; also known as reninomas) are considered benign tumors of the kidney, although there have been reports of both malignant behavior and a JGCT-related death. The clinicopathologic features of these rare tumors are well established, whereas nothing is known about their cytogenetic characteristics. The authors reported the first karyotype of a JGCT and also performed comparative genomic hybridization (CGH) and interphase fluorescence in situ hybridization (IP-FISH) analyses on the above-mentioned tumor as well as on another JGCT from which live cells were not available for karyotyping. Both tumors were also examined by electron microscopy and immunohistochemistry. The karyotype was 57 approximately 64,XX,-X,-1,-4,-6,-9,+10,-11,-13,-14, -15,+20,-22[cp10]/60 approximately 61,idem, add(19)(p13)[cp2]/46,XX[3]. The IP-FISH results were in accordance with the karyotypic findings for the first tumor, whereas Tumor 2 was found to be diploid for most investigated chromosomes, except for trisomy for chromosomes 4 and 10 and monosomy for chromosomes 9 and X. By CGH, gain of chromosomes 10 and 20 but no losses were detected for Tumor 1, whereas for Tumor 2, gain of chromosomes 4 and 10 as well as loss of chromosomes 9 and X and most of chromosome arm 11q were found. The immunohistochemical profiles were identical. Both tumors were positive for vimentin and CD34, focally positive for smooth muscle actin, and negative for cytokeratin, CD31, and actin. Gain of chromosome 10, as well as loss of chromosomes 9 and X and most of chromosome arm 11q, might be important pathogenetic events in JGCT.