Endocrine Abstracts

Introduction: The familial risks of carcinoids are not clear. There has never been a report of gastrointestinal carcinoid coexisting with horseshoe kidney.

Case presentation: We present the case of a 15 mm well differentiated metastatic small bowel NET with vascular and perineural invasion and three of four positive lymph nodes (Ki67: 1.9%, ENETS stage: pT4 pN1 pMX R1) in a 75-year-old British male with episodes of diarrhea and 24 h urinary 5HIAA: 48 (<40), pancreatic polypeptide: 955 ng/l (0–200), CgA: 50 U/l (0–30), N-terminal glucagon: 295 ng/l (0–250), C-terminal glucagon: 165 ng/l (0–150); gastrin, neurokinin A, VIP, insulin, somatostatin and serum calcium were normal and features of MEN1 absent. Interestingly, the patient had horseshoe kidney and family history of a sister with lung carcinoid (age 53), and 11 years later metastatic small bowel carcinoid and carcinoid syndrome (Ki67: 1%, CgA and urinary 5HIAA slightly elevated). The review of the literature shows that the development of primary carcinoid tumor within horseshoe kidney might be 60–85-fold higher compared to normal kidneys, while coexistence of gastrointestinal carcinoid with horseshoe kidney has never been reported so far. Previous studies using the Swedish Family-Cancer Database estimated standardized incidence ratios for offspring when their parents had a carcinoid of 4.35 (n=8, 95% CI 1.86–7.89) for small intestinal and of 4.65 (n=4, 95% CI 1.21–10.32) for colon carcinoids.

Conclusions: The case presented is the first to report coexistence of gastrointestinal carcinoid with horseshoe kidney. The familial aggregation of gastrointestinal carcinoid might underlie the need of screening programmes and gene finding studies.