Kidney and Liver Cysts in Patients with Neuroendocrine Tumors

Background: Autosomal dominant polycystic kidney disease (ADPKD) and autosomal dominant polycystic liver disease (ADPLD) are linked to major genes, PKD1 and PKD2 and PRKCSH and SEC63, respectively, plus several minor genes. However, a subset of patients with a PKD/PLD-like phenotype are not genetically resolved by analyzing the known PKD/PLD genes. In this study we evaluated a potential link between neuroendocrine tumors (NETs) and cystogenesis, based on clinical observations, potentially expanding our understanding of atypical PKD and PLD presentations Methods: Using Mayo Data Explorer (an AI search engine for Mayo Clinic EHR data), we identified 21421 patients with ICD codes for NETs and 13163 patients with codes for cystic disease of the kidney or liver, 409 patients with ICD codes for kidney and/or liver cysts and NET. Manual chart review captured family history and genetic testing in NET patients. Results: We divided the patients into 4 groups based on kidney cyst number (Table). In group 1 (clinical diagnosed ADPKD/ADPLD, N=31). Nine patients had genetic testing for cystic genes and 3 had no genetic findings, and also lacked a family history. In group 2 (≥10 cysts without a formal ADPKD/ADPLD diagnosis, N=28), 2 patients had a negative family history and negative genetic testing, 2 had positive testing for ADPKD genes, 3 underwent only testing for VHL and were negative, and 18 untested and had an unknown family history. In group 3 (5-9 cysts per kidney or liver), 7 were negative for genetic testing and had a negative family history and 6 had positive testing for ADPKD genes. Patients with ≥4 cysts were excluded from further analysis. Conclusion: A relatively high number of patients with NET had kidney or liver cysts. A few of these patients in the ADPKD/ADPLD group and many in the lower cyst number groups had a negative family history, some of which also had negative genetic testing. Therefore, this case series highlights a potential association between NETs and a cystic kidney or liver phenotype. Further investigation is needed to explore whether NET linked changes contribute to or trigger cyst formation in such atypical cases. Funding: NIDDK Support