BACKGROUND: Syndactyly is the most common upper-extremity congenital condition, and cases can be associated with genetic syndromes or arise sporadically (nonsyndromic). The purpose of this investigation was to determine rates of both malignant and benign neoplasms among pediatric patients diagnosed with nonsyndromic syndactyly compared to matched controls. METHODS: The TriNetX US Collaborative database was queried using International Classification of Disease, 10th Revision codes to identify patients aged 10 years or younger diagnosed with syndactyly. Patient history of syndactyly was utilized to categorize patients into 2 cohorts. These cohorts were propensity-matched by age, sex, race, ethnicity, and congenital malformation syndromes. Subsequent rate of neoplasms was compared between patients with and without syndactyly. RESULTS: A total of 7478 patients aged 10 years or younger diagnosed with syndactyly were identified. After 1:1 propensity matching, both cohorts included 5461 patients. The rate of digestive malignancies was significantly higher int he syndactyly cohort than that in the control cohort. The rate of benign neoplasms was significant at >5 years follow-up duration (P = .016, 95% CI 0.001-0.005) but was not significant at 1 year or 1 to 5 years. Similarly, rate of any neoplasm was significant at >5 years follow-up duration (P = .013, 95% CI 0.001-0.005) but not at 1 year or 1 to 5 years. CONCLUSIONS: Nonsyndromic syndactyly is associated with an increased rate of benign neoplasms and digestive malignancies. Further investigation is needed to better understand the relationship between the syndactyly phenotype and risk of malignancy.
