Combined Central Hypothyroidism and Adrenal Insufficiency Associated with Retinoic Acid Therapy for Cutaneous T-Cell Lymphoma

Abstract

Background/objective: Although retinoid-associated central hypothyroidism has been reported on several occasions, there are very few studies on retinoid-associated central adrenal insufficiency. Here, we present the case of a patient with alitretinoin-induced central hypothyroidism and adrenal insufficiency.

Case report: An 86-year-old man with a diagnosis of cutaneous T-cell lymphoma, treated with oral alitretinoin 30 mg po daily, topical steroids, and ultraviolet light therapy presented to the emergency department with generalized weakness, decreased energy, orthostasis, and unexplained falls. Thyroid-stimulating hormone (TSH) was 0.31 mIU/L (normal range: 0.4-4.4) from 1.93 before alitretinoin therapy, whereas free thyroxine was 5.7 pmol/L (normal range: 8-18) and the AM cortisol was 40 nmol/L (normal range: 120-535); these values were suggestive of central hypothyroidism and adrenal insufficiency. Adrenocorticotropic hormone (ACTH) was not measured because of a laboratory error. Alitretinoin was stopped, and one dose of hydrocortisone 100mg IV was initiated, followed by maintenance doses of oral hydrocortisone 20mg qam and 10mg qpm. Levothyroxine (50μg ) daily was started 24 hours later. After stopping hydrocortisone for 24 hours, the AM cortisol and ACTH levels were 406 nmol/L and 2.18 pmol/L (normal range:1.6-13.9), respectively. He was discharged on thyroid hormone replacement therapy and glucocorticoids. Repeat thyroid function tests 6 weeks later showed a TSH of 0.4 mIU/L, and free thyroxine of 9.7 pmol/L.

Discussion: Alitretinoin activates nuclear receptors called retinoic acid receptors and retinoid X-receptors. Retinoic acid receptors and retinoid X-receptors are widely expressed in the anterior pituitary gland. RXR-selective ligands such as retinoids can suppress TSH secretion, resulting in central hypothyroidism. Retinoids have also been shown to decrease ACTH secretion, which can result in central adrenal insufficiency.

Conclusion: Although central adrenal insufficiency and hypothyroidism have not been commonly reported in patients taking retinoids, they should always be considered when caring for these patients.

Keywords: ACTH, adrenocorticotropic hormone; FSH, follicle-stimulating hormone; HPA, hypothalamic-pituitary-adrenal; RARs, retinoic acid receptors; RXRs, retinoid X-receptors; TSH, thyroid-stimulating hormone; adrenal insufficiency; central hypothyroidism; retinoic acid.