Nephrogenic adenoma of the urinary bladder. Histologic and cytologic observations in a case.

The histologic and cytologic features of multiple tissue and voided urine specimens from a man with nephrogenic adenoma of the urinary bladder are described. The urinary cytology showed papillary fragments, with cells showing palisade formation. The cells were round to oval, with a centrally placed nucleus with a fine chromatin pattern. These cells were identical to those seen in a low-grade papillary transitional-cell carcinoma. Tissue biopsy is needed to separate these two very different pathologic conditions.