Mitotane-Induced Hypothyroidism and Dyslipidemia in Adrenocortical Carcinoma: Sex Differences and Novel Evidence from a Thyroid Cell Model

Adrenocortical carcinoma (ACC) is a rare and aggressive cancer with limited treatment options, commonly managed with mitotane, which can cause serious side effects, including central hypothyroidism and dyslipidemia. This study aimed to evaluate the incidence, clinical features, and relationship between mitotane-induced central hypothyroidism and dyslipidemia in ACC patients, as well as to investigate mitotane's direct toxic effects on thyroid cells. Thirty-eight ACC patients treated with mitotane for at least six months were monitored for thyroid function and lipid profiles. Central hypothyroidism developed in 50% of patients with normal baseline thyroid function, mostly women, who were at higher risk. Dyslipidemia occurred in 40% of patients, more frequently in men, and appeared earlier than hypothyroidism. In vitro experiments on rat thyroid cells demonstrated a dose-dependent toxic effect of mitotane on cell viability. No significant link was found between hypothyroidism and dyslipidemia risk. These findings reveal sex-specific susceptibilities to mitotane toxicity and provide novel evidence of direct mitotane-induced thyroid cell damage. This insight supports the need for careful thyroid and lipid profile monitoring during mitotane treatment and may inform the development of safer therapies for ACC.