Histopathological Review and Re-Categorization of Thyroid Malignancies Based on Who Classification of Endocrine Tumors, 2022

Thyroid cancer (TC) is the commonest endocrine malignant tumor whose incidence has been increasing steadily for decades in the world. This alarming rise in the incidence of thyroid malignancies, even in the face of low and stable and mortality rates is thought to be predominantly driven by overdiagnosis; notably evident in the case of papillary thyroid tumors. This has led to otherwise indolent tumors being aggressively managed causing potential harms to patients and levying unnecessary costs on an already overburdened healthcare system. The 5th edition of the World Health Organization (WHO) classication of endocrine tumors, released in 2022, has introduced several changes to the nomenclature, grading and prognostication of thyroid proliferations based on pathologic features and molecular prole that can help in improving risk stratication by categorizing tumors based on histological and molecular characteristics, thereby reducing the burden of diagnosis of incidental and indolent lesions, as well as de-escalate the treatment. The present study attempts to review the histopathological diagnosis of all previously reported thyroid neoplasms at our institution and reclassify them according to the recently updated criteria.