Abstract
Acquired cystic disease of the kidney (ACDK) has a strong relationship with dialysis. The incidence of renal cell carcinoma is high in ACDK. However, the cytologic features of ACDK-associated renal cell carcinoma (RCC) in voided urine have rarely been reported. A 37-year-old male with a long history of IgA nephropathy presented with a both-kidney mass, detected by magnetic resonance imaging. Urine cytology smears showed moderately cellular characteristics and were composed of three-dimensional clusters and single cells. These atypical cells showed abundant foamy cytoplasm, and the nuclei were round and showed fine chromatin, with single or multiple small nucleoli. In addition to atypical cells, smears showed many isomorphic erythrocytes in the background. In immunocytochemistry, these atypical cells showed positivity for CD15. The diagnosis of ACDK-associated RCC was established from the subsequent histologic examination of both kidneys. When urine cytology from long-term dialysis patients reveals a cluster of atypical cells with abundant foamy cytoplasm, finely granular chromatin, and nucleoli, one should suspect an ACDK-associated RCC. The correlation of clinical presentation and imaging analysis with cytologic findings is important, and can be further supplemented by immunocytochemistry to differentiate it from other tumor cells.
