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Case 12 - Discussion

Surgical Pathology Case


Minimally invasive follicular carcinoma, confined to thyroid

  • Diagnosis of follicular carcinoma is almost purely based on the presence of capsular and/or vascular invasion. Cytological features are not reliable.
  • Thus, the entire capsule should be submitted for evaluation of invasion.
  • Tangential cut may create artificial capsular invasion with entrapment of thyroid tissue in the capsule
  • Prior needle biopsy can cause entrapment of thyroid tissue in the capsule or "invasion" outside of the main nodule. Need to review the patient history, and also look carefully at the possible needle track for infarct-like glandular necrosis or hemosiderin deposits
  • It is very difficult to make the diagnosis of follicular carcinoma on frozen (unless there is clear evidence of capsular invasion) or FNA