A 35-year-old woman undergoes hemithyroidectomy for a 3.5 cm follicular thyroid lesion. Histopathology shows transcapsular and vascular invasion with >4 foci of vascular invasion. According to WHO 2022 classification, this is best categorized as:

• A Minimally invasive follicular carcinoma
• B Encapsulated angioinvasive follicular carcinoma (low risk)
• C Follicular adenoma with atypical features
• D Widely invasive follicular carcinoma ✓

Explanation

Widely invasive follicular carcinoma shows widespread infiltration of adjacent thyroid tissue or extensive vascular invasion (>4 vascular invasion foci). This has a significantly worse prognosis than minimally invasive disease and warrants completion thyroidectomy and radioactive iodine ablation. Minimally invasive follicular carcinoma (capsular invasion only, no angioinvasion) carries an excellent prognosis and may be managed more conservatively.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.