RÉSUMÉ
Objective To investigate the clinical and pathological characteristics of nephrogenic adenoma. Methods Eleven patients were diagnosed as nephrogenic adenoma including 5 men and 6 women, aged 37-78 years (56 on average). The pathological findings in all cases of nephrogenic adenoma were presented with a review of the literature. Results Eleven cases of nephrogenic adenomas were evaluated, 2 cases were in ureter and 9 cases were in the bladder. Eight of the 9 bladder cases underwent TUR-BT surgery in continuous epidural anesthesia, 1 case underwent partial cystectomy with general anesthesia. A right ureteroscopy and left ureterolithotomy were performed respectively in continuous epidural anesthesia for the 2 cases in ureter. The final diagnosis was based on histopathological findings. For all of cases, 8 cases were diagnosed as nephrogenic adenomas, 2 cases as atypical nephrogenic adenoma and 1 case as nephrogenic adenoma with malignant transformation. The microscopic appearance of nephrogenic adenoma demonstrated that morphology closely resembled aberrant tubules of the kidney. In addition, atypical nephrogenic adenomas appeared as the presence of cytologic atypia, including nuclear enlargement, nuclear hyperchromasia and prominent nucleoli. The morphologic changes of nephrogenic adenomas with malignant transformation were that tumor cells retained the basic structural characteristics of typical nephrogenic adenomas, and the similar morphological cells lost adhesion ability among cells and presented diffuse solid growth in the surrounding area.Intravesical perfusion was further performed for treating the patients with atypical nephrogenic adenomas or nephrogenic adenomas with malignant transformation. The mean patient follow up was 46 months (range, 24- 104 months), and there was only 1 case of recurrence. Conclusions Nephrogenic adenoma is an uncommon benign lesion of the urinary tract. The symptoms and cystoscopic manifestations are not unique. We reported one patient of nephrogenic adenomas with malignant transformation and provided some evidence for malignant alteration in morphology and invasive behavior. All patients underwent local excision of the lesions. Intravesical perfusion was further performed for treating the patients of atypical nephrogenic adenomas or nephrogenic adenomas with malignant transformation. Whether it is nephrogenic adenoma or atypical nephrogenic adenoma, long-term follow-up after treatment is necessary.