Clusters of Primary Cilia in Proximal Tubules Are Metaplastic Changes Secondary to Proximal Tubular Injury

Abstract

Synchronous occurrence of dual pathology is known to occur, but triple pathology in the kidney is an extraordinarily rare phenomenon. Our unique case showed incidental triple pathologies in the same kidney. A left nephroureterectomy specimen received in our anatomic pathology department revealed a high-grade papillary urothelial carcinoma, cystic clear cell carcinoma, and multiple nodules of papillary renal cell carcinoma of unknown malignant potential (former papillary renal cell carcinoma, according to size criteria of 0.5-2.0 cm, WHO classification). A 61-year-old man came to the urology department. His medical history was significant for smoking, hypertension, sleep apnea, and coronary heart disease. No family history or genetic history was given in his chart. Gross examination revealed the kidney weighed 220 g and measured 15 × 7 × 5 cm. Serial sectioning of the specimen revealed a single papillary lesion in the renal pelvis measuring 5 × 5 × 3 cm without any areas of hemorrhage or necrosis. Incidental findings covering the entire surface of kidney included multiple cystic and solid golden yellow nodules ranging from 1 to 12 mm. Microscopic examination showed a high-grade papillary urothelial carcinoma, cystic clear cell carcinoma, and papillary neoplasm of uncertain malignant potential (former papillary renal cell carcinoma). Additional findings included multiple renal cell papillomatosis, cortical cysts, and arterial arteriosclerosis. Immunohistochemistry showed positive staining for CD10 and p63 and negativity for P504S. Our case is unique in that 3 distinct pathologies were present in the same kidney. we have not come across any literature describing multiple entities including high-grade papillary urothelial carcinoma, cystic clear cell carcinoma, papillary renal cell carcinoma, cortical cysts, and other chronic changes in 1 kidney. This unusual constellation of papillary renal neoplasms raises the question of genomic alterations.