Patients with Diffuse Liver Hemangioma likely have severe hypothyroidism which is caused bye type 3 Iodothyronine deiodinase, this enzyme cleaves off iodine and inactivates it the body. Aggressive Thyroid Replacement therapy may balance this mechanism. Monitoring TSH levels can help determine the dosage of thyroid replacement medication to use. Once the liver Hemangioma has involuted thyroid replacement therapy can be discontinued. Traditionally the management of this type of liver hemangioma did not include Aggressive Thyroid Replacement Therapy, the hemangioma was managed but the child was impaired mentally due to hypothyroidism. Understanding the management of TSH levels has prevented this complication.