A 55-year-old patient undergoes total thyroidectomy for a 3 cm follicular thyroid carcinoma. On histology, there is capsular invasion with 2 foci of vascular invasion. According to the 2022 WHO classification and ATA guidelines, this tumour is best classified as:
- A Minimally invasive follicular thyroid carcinoma (FTC) — low risk
- B Widely invasive FTC — high risk
- C Encapsulated angioinvasive FTC with limited vascular invasion (2-3 vessels) ✓
- D Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)
Correct answer: C. Encapsulated angioinvasive FTC with limited vascular invasion (2-3 vessels)
Explanation
The 2022 WHO classification divides encapsulated FTC by extent of vascular invasion: limited vascular invasion (fewer than 4 vessels) carries intermediate risk, while extensive vascular invasion (4 or more vessels) carries high risk of distant metastasis. Widely invasive FTC lacks a capsule and shows gross infiltration. NIFTP is a non-invasive follicular tumour with papillary nuclear features and is a distinct low-risk entity. Two foci of vascular invasion places this in the limited-invasion category.
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.