Table II.

Thyroid FNAC diagnostic categories

Thy 1	Thy 2	Thy 3		Thy 4	Thy 5
		Thy 3F	Thy 3A
Non-diagnostic	Non-neoplastic, e.g. colloid nodule or thyroiditis	Follicular lesion	Atypia present	Suspicious of thyroid cancer	Diagnostic of thyroid cancer
Repeat FNAC	No follow-up if no suspicious US features and no clinical suspicion of thyroid cancer	Diagnostic hemithyroidectomy* Consider total thyroidectomy in lesions >4 cm where incidence of malignancy is higher	Repeat ultrasound and FNAC If second Thy 3A cytology obtained, discuss at MDT and consider diagnostic hemithyroidectomy*	Discuss at MDT Diagnostic hemithyroidectomy*	Discuss at MDT Appropriate further investigations for staging where indicated Total thyroidectomy ±  central node clearance in appropriate high risk patients

^*Hemithyroidectomy consists of removal of a thyroid lobe and the isthmus