Juvenile Polyps in Denmark From 1995 to 2014.

BACKGROUND: Juvenile polyps in the large bowel are rare but the most common type of polyp in children. The prevalence and incidence are unknown, and few studies exist on the occurrence in adults. They are considered not to harbor any malignant potential unless they are part of the hereditary juvenile polyposis syndrome.

OBJECTIVE: We aimed to study the demographics of juvenile polyps in Denmark in a 20-year period from 1995 to 2015 in both adults and children. This is the first report on the occurrence, anatomic localization, and reoccurrence of these polyps in a whole population.

DESIGN: Data from all of the patients who had been diagnosed with 1 or more juvenile polyp from January 1, 1995, until December 31, 2014, were obtained.

SETTINGS: The study was conducted based on patients registered in the nationwide pathological register in Denmark, the Danish Pathology Data Bank.

PATIENTS: We detected a total of 1772 patients who had 2108 juvenile polyps removed (male = 946; female = 826).

MAIN OUTCOME MEASURES: We noted the sex, age, number, reoccurrence, and localization of polyps.

RESULTS: Of the detected juvenile polyps ≈75% were detected in adults and ≈25% in children. Approximately 96% of the patients had a single juvenile polyp without reoccurrence, 1% fulfilled the diagnostic criteria for juvenile polyposis syndrome (more than 5 polyps), and 5% had multiple juvenile polyps (2-5 polyps). The incidence in the Danish population can be estimated to be between 1:45,000 and 1:65,000.

LIMITATIONS: Miscoding or misclassification in the register cannot be ruled out. We only have data for the 20-year period, limiting the evaluation of reoccurrence, and no data for the endoscopic removal procedures.

CONCLUSIONS: We conclude that juvenile polyps are rare, with the majority found in adults, and most often found as a single juvenile polyp. A subgroup of patients have juvenile polyposis syndrome, which requires follow-up.