SUN-713 Prevalence of Renal Cysts in Patients with Carney Complex

Abstract

In the general population renal cysts appear most commonly in patients >50 y and in men. Among published studies, the prevalence of renal cysts detected by MRI was 27%, detected by CT was 20-41%, and detected by US was 4-17% (Mensel, et al., 2018; Choi, et al., 2016). In these studies, the male to female ratio in patients with renal cysts ranged from 1.4:1 to 2.93:1. Carney complex (CNC) is an autosomal dominant multiple endocrine neoplasia and lentiginosis syndrome predominantly caused by aberrant cAMP-protein kinase A (PKA) signaling mostly (but not always) due to germline inactivating defects in PRKAR1A which encodes the regulatory subunit type 1α of PKA. In a small retrospective study, 5 of 9 subjects with CNC had renal cysts on MRI or CT (Ye, et al., 2017). This same study evaluated the development of renal cysts in kidney-specific Prkar1a knockout mice, where all mice developed a renal cystic phenotype. To determine the prevalence of renal cysts, we performed a retrospective cohort study of patients with CNC evaluated at our institution between 1984 and 2019 who underwent renal imaging with MRI, CT, and/or US. We hypothesized that CNC leads to renal formation of cysts in humans, with increased number of renal cysts and earlier age at detection. 117 patients with CNC (69 female [59%], 48 male [41%]) were evaluated with renal imaging (56% MRI, 41% CT, 3% US). Of these, 39 (33%) patients had renal cysts that were first detected on imaging between the ages of 13 and 58 y (mean age at diagnosis 37.1 ±12.7 y; 5 [13%] 12-19 y, 5 [13%] 20-29 y, 10 [26%] 30-39 y, 11 [28%] 40-49 y, and 8 [21%] 50-59 y). The mean number of cysts was 1.3 ±0.7, and mean dominant cyst size was 1.2 ±0.9 cm. Average creatinine at diagnosis was 0.8 ±0.2 mg/dl. Of the patients with renal cysts, 22 were female (56% of patients with renal cysts, 32% of females with CNC that underwent renal imaging) and 17 were male (44% of patients with renal cysts, 35% of males with CNC that underwent renal imaging). There was no difference in the prevalence of renal cysts between males and females (35% vs 32%, p=.70, for a 1.1:1 ratio). Age, number, and dominant cyst size were also not different between sexes (p=.51, p=.84, and p=.26, respectively). However, creatinine levels were higher in males (0.9 ±0.1 vs 0.7 ±0.1, p<.001). All 39 patients with renal cysts had defects in PRKAR1A as compared to 73 of 78 (94%) patients with CNC that did not have renal cysts on imaging (p=.17). In conclusion, our data demonstrate that there is a high prevalence of renal cysts in patients with CNC with both males and females being affected equally, in contrast to the majority of previously reported population studies. They also suggest that renal cysts may develop in patients with CNC at a younger age. These results can be further validated by comparison to a cohort of healthy controls.