'Indeterminate' cystic lesion of the kidney partially lined by small cells with clear cytoplasm--malignant or benign?

摘要

Complex renal cysts, which present radiographically as "indeterminate for malignancy" (Bosniak category III), can prove challenging both pathologically and clinically. We report a case of a renal cyst that, by standard radiographic and histologic criteria, should have been diagnosed as a malignant cystic renal cell carcinoma. However, the cytogenetic profile appeared more closely consistent with cystic renal adenoma or low-grade papillary renal cell carcinoma--tumors with limited metastatic potential. We postulate that other, similarly complex, renal cysts might also be more precisely defined by meticulous histopathologic examination, supported by cytogenetic study.