CLINICOPATHOLOGICAL AND INTERPHASE CYTOGENETIC ANALYSIS OF PAPILLARY (CHROMOPHILIC) RENAL-CELL CARCINOMA

Trisomy 7 and 17 with deletion of Y is typical of papillary renal cell adenoma (PRCA), and additional alterations occur in the putative gene tic progression toward papillary renal cell carcinoma (PRCC), Our stud y correlated aneuploidy with clinicopathologic features in PRCCs, We u sed fluorescence in situ hybridization to assess copy number for chrom osomes 7, 8, 10, 12, 16, 17, and Y in 16 PRCCs and surrounding benign tubular parenchyma from 15 patients by use of a satellite (centromere) probes on deparaffinized tissue sections, We then compared the patter n of monosomy/nullisomy or trisomy/polysomy/hemidisomy to clinicopatho logic parameters, Nine tumors (58% Group 1) showed the numeric aberrat ions typical of PRCAs and PRCCs, with gains of 7 and 17 and loss of Y, We also identified four trisomies of 12 and 16 and one of 8 in Group 1, The remaining seven cases (Group 2) were cytogenetically atypical, Two displayed borderline loss of chromosome 7, although trisomy 17 was present in both, Five had trisomy 7, but none exhibited chromosome 17 alterations, and two exhibited a gain of Y, Neoplasms in Group 2 were less often multicentric than were Group 1 tumors, and they contained foamy macrophage infiltrates less often, One chromophilic carcinoma wi th abundant clear cells and another with oncocytic features exhibited Group 2 chromosomal profiles. One patient (nuclear grade 4) died from disease, and 14 had no evidence of carcinoma at the last follow-up. We concluded that PRCCs represent a histologically and genotypically het erogeneous group of tumors, If PRCAs consistently exhibit +7, +17, and -Y, it is uncertain whether PRCCs always evolve directly from such le sions, The presence of genotypic heterogeneity might reflect histologi c variants of PRCCs, which overlap with other types of RCC, PRCC is ge nerally an indolent neoplasm, despite a high frequency of chromosomal aneuploidy.