CD4 and endometrioid stromal sarcoma: The primary hypothesis is the direct influence on the thyroid gland by SARS-CoV-2 causing euthyroid sick syndrome (ESS), resulting in decreased levels of serum T3 and/or T4 without increased secretion of TSH.19 In patients with COVID-19, ESS may be directly caused by the infection of thyroid cells with SARS-CoV-2.