Mutagen accumulated in cyst fluid of acquired cystic disease of the kidney

Acquired cystic disease-associated renal cell carcinoma is the most common subtype in long-term dialyzed patients: Central pathology results according to the 2016 WHO classification in a multi-institutional study

New pathological subtypes of renal cell carcinoma (RCC) were designated in the 2016 World Health Organization (WHO) classification corresponding to the features commonly seen in patients with end-stage renal disease (ESRD). To determine the clinicopathological findings of new subtypes, we reanalyzed all sections from 315 kidneys in 291 ESRD patients bearing RCC tumors surgically resected in three Japanese institutes by the central pathologist. Clear cell RCC was diagnosed in 144 kidneys (45.7%), acquired cystic disease (ACD)-associated RCC in 100 (31.7%), papillary RCC in 41 (13.0%), and other minor subtypes in 30 (9.52%). Multivariate analysis showed that longer duration of dialysis, young age, and male sex were independent prognostic clinical factors for the occurrence of ACD-associated RCC. ACD-associated RCC included more WHO/International Society of Urologic Pathology (ISUP) grade 3/4 cases compared to other RCCs. In contrast, other unfavorable findings were less frequent in ACD-associated RCC, including the presence of a sarcomatoid component, lymphovascular invasion, and necrosis. In conclusion, ACD-associated RCC is a common histology in Japanese patients with ESRD. In addition, ACD-associated RCC showed more cases with a higher WHO/ISUP grade, but fewer cases with other unfavorable pathological features, suggesting a favorable prognosis of ACD-associated RCC.