Diffuse Infantile Hepatic Hemangiomatosis: A Rare Cause of Consumptive Hypothyroidism.

Infantile hepatic hemangiomatosis (IHH) is a rare benign vascular tumor of infancy, defined by multiple angiomatous lesions diffusely replacing the hepatic parenchyma. Its clinical course can be severe due to systemic complications, particularly consumptive hypothyroidism and high-output heart failure. We report the case of a four-month-old female infant admitted for abdominal distension evolving over two weeks. Physical examination revealed massive hepatomegaly (hepatic span of 14 cm) with abdominal-thoracic collateral venous circulation and no cutaneous hemangiomas. Laboratory workup showed normochromic normocytic non-regenerative anemia (hemoglobin = 6.7 g/dL), hepatic cytolysis (aspartate aminotransferase = 3× normal), cholestasis (alkaline phosphatase = 188 IU/L, gamma-glutamyl transferase = 335 IU/L), and a prothrombin time reduced to 54%. Alpha-fetoprotein was 470 ng/L. Abdominal MRI revealed multiple rounded hepatic lesions, T1 hypointense and T2 hyperintense with diffusion restriction and progressive centripetal contrast enhancement, consistent with diffuse IHH. Cardiac (echocardiography) and cerebral (transfontanellar ultrasound) assessments were normal. Systematic thyroid function tests revealed severe consumptive hypothyroidism, with thyroid-stimulating hormone level of 500 µIU/mL and free T4 of 6 pmol/L, without antithyroid antibodies. Management included progressive propranolol (Hemangiol®) up to 3 mg/kg/day, levothyroxine at 20 µg/kg/day, and red blood cell transfusion. At the six-month follow-up, thyroid function had normalized, and hepatic lesions showed significant regression. This case highlights the necessity of systematic thyroid function screening in all infants with IHH and illustrates the efficacy of propranolol in managing this rare but potentially life-threatening condition.