Incidence of pediatric Horner syndrome and the risk of neuroblastoma: A population-based study

Objective: To describe the incidence of pediatric Horner syndrome and the risk of occult malignancy in a population-based cohort. Methods: The medical records of all pediatric patients (aged <19 years) residing in Olmsted County, Minnesota, who received diagnoses of Horner syndrome from January 1, 1969, through December 31, 2008, were retrospectively reviewed. Results: Horner syndrome was diagnosed in 20 pediatric patients during the 40-year period, yielding an age-and sex-adjusted incidence of 1.42 per 100 000 patients younger than 19 years of age (95% confidence interval [CI], 0.80-2.04). Eleven of the 20 patients (55%) had a congenital onset, for a birth prevalence of 1 in 6250 (95% CI, 3333-10 000), while the remaining 9 (45%) had acquired syndromes. Seven of the 11 (63.6%) patients with congenital cases had a history of birth trauma, while the remaining 4 (36.4%) had no identifiable cause. Six of the 9 (66%) acquired cases occurred following surgery or trauma, while the remaining 3 (33%) had no known etiology. None of the 20 patients (95% CI, 0.0%-16.8%) were found to have a neuroblastoma or other malignancy during a mean follow-up of 56.5 months (range, 0-256.9 months). Conclusions: The incidence of pediatric Horner syndrome in this population was 1.42 per 100000 patients younger than 19 years, with a birth prevalence of 1 in 6250 for those with a congenital onset. Birth, surgical, or other trauma occurred in 13 (65%) of the patients, while none were found to have an underlying mass lesion, suggesting a need for reappraising current recommendations for extensive evaluations in these patients.