Neuroendocrine Tumors May be Associated With Atypical Cystic Disease of the Kidneys or Liver

Rationale & Objective Neuroendocrine tumors (NETs) are seldom associated with kidney and liver cysts except with rare genetic diseases such as von Hippel-Lindau syndrome. However, we observed that some patients with NETs may also have kidney and/or liver cysts, sometimes mimicking autosomal dominant polycystic kidney disease (ADPKD) or autosomal dominant polycystic liver disease (ADPLD). We hypothesized that tumor characteristics may drive cyst growth, even in the absence of a genetic predisposition. Study Design Retrospective Case Series. Setting & Participants An electronic health record-based cohort from Mayo Clinic, including patients with NETs and kidney and/liver cysts identified using ICD-9 and ICD-10 codes, followed by manual chart review. Exposure Diagnosis of neuroendocrine tumor and kidney or liver cysts Outcomes Cyst burden, clinical diagnosis of ADPKD or ADPLD, family history, genetic testing results, and kidney function. Analytical Approach Patients with ICD codes for NETs and kidney or liver cysts underwent detailed chart review. Individuals with confirmed genetic diagnosis or family history of ADPKD/ADPLD were excluded. Patients were stratified by cyst burden and clinical characteristics. Results Among 409 patients with ICD codes for NETs and cystic disease, 316 had confirmed NET and kidney or liver cysts. The cohort was stratified by clinical diagnosis (ADPKD/ADPLD, n=32), Cyst burden (>10 cysts (n=28) or 5-9 cysts (n=106)). Imaging and clinical findings are presented for 32 patients who have a clinical diagnosis of ADPKD/ADPLD or atypical cystic kidney disease. Serial cyst burden was reviewed for 3 patients who demonstrated an increase in cyst burden following NET diagnosis. Limitations Retrospective study, limited availability of genetic testing, and small sample size in subgroups. Conclusions This case series highlights a potential association between NETs and cystic kidney and liver disease, which sometimes phenotypically mimics ADPKD or ADPLD.