Involvement of 12q12-13 Is a Nonrandom Chromosome Change in Renal Oncocytoma
To the Editors:
Cytogenetically, renal oncocytomas constitute a heterogeneous group of benign renal tumors with at least two different subgroups: 1) those with coincident loss of the Y chromosome and chromosome 1, and 2) those with rearrangements affecting band 11q13 . We recently found a second case of oncocytoma with a 12q13 rearrangement, similar to that previously reported .
A 7-cm tumor was discovered incidentally in the upper pole of the right kidney of a 75-year-old man. No adenopathies or intra-abdominal or pulmonary metastases were found. A radical nephrectomy was performed. Histology revealed the typical features of renal oncocytoma: uniform cells with homogeneous granular eosinophilic cytoplasm and small round nuclei, no necrosis, and abundance of mitochondria by electron microscopy.
Twenty G-banded metaphases were analyzed after 5-day culture of a surgical tumor sample, and all exhibited the karyotype 46,XY,t(1;2)(p12; q31),t(12;19)(q12-13;p13).We previously described a similar 12q rearrangement in a histologically identical renal oncocytoma . We thus suggest that involvement of 12q12-13 could characterize a third cytogenetically abnormal subgroup of renal oncocytoma.