Papillary renal cell carcinoma. A morphologic and cytogenetic study of 11 cases.

Most renal cell carcinomas are characterized by constant loss of the 3p13-pter chromosome segment and a frequent gain of the 5q22-qter segment. A comparative histologic and cytogenetic investigation of large series of renal cell carcinomas now shows that purely papillary tumors differ from the more common nonpapillary form not only in their morphologic characteristic, but also in karyotype changes observed. All of the 11 papillary tumors of this study failed to show any rearrangement of the critical 3p segment, and trisomy of the 5q22-qter segment has never been found. The gain of chromosome 17 was detected only in papillary renal cell carcinomas. Other nonrandom karyotype changes occurred with the same incidence in both types of tumor. Thus, some karyotype alterations in renal cell carcinomas could perhaps be regarded as a genetic mechanism responsible for the phenotype of conversed tubular cells.