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

Abstract

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.

Consumptive hypothyroidism: a case report and review of the literature

“…In a recent case report, the expression of D3 activity in the resected tumour was found to be significantly higher than the mean of placental tissues of four subjects. 4 The tumoral D3 expression in these vascular lesions together with the disappearance of hypothyroidism after liver transplantation or HHE involution support the concept that this endocrinopathy is due to excessive degradation of thyroid hormones. 3,4 The rate of T4 degradation is a product of the enzyme activity and the mass of the HHE; hence the large variations in values of TSH and fT4 reported in the previous cases.…”

“…4 The tumoral D3 expression in these vascular lesions together with the disappearance of hypothyroidism after liver transplantation or HHE involution support the concept that this endocrinopathy is due to excessive degradation of thyroid hormones. 3,4 The rate of T4 degradation is a product of the enzyme activity and the mass of the HHE; hence the large variations in values of TSH and fT4 reported in the previous cases. It has been reported that the most rapid rate of T4 degradation is associated with the proliferative phase of HHE.…”

“…Possible secretion of TSH-like factor in patients with HHE may explain why in some cases a high dose of thyroid replacement therapy may treat the clinical hypothyroidism and restore fT4 to reference level, with TSH remaining markedly elevated. 2,4 There are various medical modalities of treatment for HHE. It is usually treated successfully with steroids and/or a-interferon.…”

“…3,11 In some of the previous cases, children required extremely high doses of T4, T3 or combined thyroid replacement therapy. 4,12,13 Doses ranging between 5 and 94 mg/kg/d have been reported. 8 (For comparison, in conventional hypothyroidism the thyroid replacement therapy dose that maintains euthyroid status in infants ranges from 5 to 10 mg/kg/d.)…”

Hashimoto's Thyroiditis in Children and Adolescents

“…If anti-TPO antibodies are absent, less common etiologies of primary hypothyroidism should be considered for example transient hypothyroidism due to postsubacute thyroiditis, hypothyroidism related to external irradiation (69) and consumptive hypothyroidism due to the inactivation of thyroid hormone by the paraneoplastic expression of type III iodothyronine deiodinase, mostly in vascular tumors (70). The typical patient with hypothyroidism secondary to HT has an elevated TSH, a low fT4, and positive anti-TPO antibodies.…”