Increased type 3 iodothyronine deiodinase activity in a regrown hepatic hemangioma with consumptive hypothyroidism

Introduction Infantile hepatic hemangioma with consumptive hypothyroidism is a rare condition. Case report A 4-month-old girl presented with diffuse hepatic hemangiomas during treatment of congenital hypothyroidism. Serum reverse triiodothyronine was elevated, and her hypothyroidism improved concomitant with involution of the hemangioma following prednisolone and interferon-α administration. At 20 months of age, 7 months after discontinuing prednisolone and interferon-α, a focal hemangioma regrew from one of the previous lesions and was surgically resected. The expression and activity of type 3 iodothyronine deiodinase (D3) were elevated in the resected tumor tissue compared with placenta. Discussion Here, we describe a patient with consumptive hypothyroidism and diffuse infantile hepatic hemangiomas, one of which regrew after involution following pharmacotherapy. The etiology of elevated D3 activity is also discussed. Conclusion It is important to identify infantile hepatic hemangioma in patients with hypothyroidism refractory to hormone replacement therapy, who have low free triiodothyronine despite high thyrotropin and normal free thyroxine levels, and long-term follow-up will be needed for these patients.