TPO and spindle cell hemangioma: Serum anti-TPO antibody levels were significantly higher in SCH+ participants (mean: 116.5 ± 34.8 IU/mL) compared to SCH- participants (mean: 22.1 ± 5.6 IU/mL) and controls (mean: 18.5 ± 3.2 IU/mL) (P < 0.001).