SARS-CoV-2 detection in primary thyroid sarcoma: coincidence or interaction?

INTRODUCTION: Thyroid dysfunctions associated with SARS-CoV-2 are emerging in scientific literature. During the second COVID-19 epidemic spread, we evaluated a patient with the suspect of subacute thyroiditis. METHODS AND RESULTS: Specimen from fine-needle aspiration of a hypoechoic undefined area was analyzed for cytology and for SARS-CoV-2 detection. SARS-CoV-2 was retrieved by real-time polymerase chain reaction on the cytologic sample, which was then cultured on Vero E6 cells and demonstrated to be cytopathic. Whole-genome sequence was deposited. Histological exam diagnosed a rare case of primary thyroid sarcoma with diffuse and strong expression of mouse double minute 2 homolog (MDM2) oncoprotein. Ultrastructural examination confirmed, in several neoplastic cells, the presence of viral particles in cytoplasmic vacuoles. CONCLUSIONS: In our hypothesis, SARS-CoV-2 and sarcoma coexistence could represent a synergistic interplay, ultimately favoring both viral persistence and tumor proliferation: the overexpression of MDM2 in tumor cells might have generated a favorable immunological niche for SARS-CoV-2 localization and, in turn, SARS-CoV-2 could have favored tumor growth by inducing MDM2-mediated p53 downregulation. Functional studies are needed to confirm this suggestive pathway.