Role of Histopathology in Diagnosis and Management of Thyroid Nodules
Histopathology plays a critical role primarily after initial cytological assessment by fine-needle aspiration cytology (FNAC) in thyroid nodules. FNAC results are categorised using the Royal College of Pathologists modification of the British Thyroid Association (BTA) system, ranging from Thy1 (inadequate) to Thy5 (malignant), guiding further management steps NICE NG230.
When FNAC results are indeterminate or suspicious (Thy3a, Thy3f, Thy4, Thy5), histopathological examination of surgically excised tissue (diagnostic hemithyroidectomy or total thyroidectomy) is essential to establish a definitive diagnosis and guide treatment NICE NG230. For example, Thy3f (suggesting follicular neoplasm) typically leads to diagnostic hemithyroidectomy for histopathological evaluation NICE NG230.
Histopathology confirms malignancy, determines tumour type, and assesses features such as capsular or vascular invasion, which are crucial for staging and prognosis. This information directs further management, including the extent of surgery and the need for adjuvant therapies like radioactive iodine NICE NG230.
In cases where FNAC is inadequate (Thy1), repeat sampling or diagnostic surgery may be considered to obtain tissue for histopathological diagnosis NICE NG230. Thus, histopathology is the definitive diagnostic tool following cytology and is integral to planning appropriate surgical and oncological management of thyroid nodules NICE NG230.