CytopathologyIntermediate

Thyroid fine needle aspiration — follicular lesion

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Clinical history

46-year-old with a 28 mm solitary thyroid nodule.

Specimen

Ultrasound-guided fine needle aspiration · Stain: Papanicolaou

Microscopic description

Cellular smears with microfollicular architecture, scant colloid and mild nuclear enlargement without papillary nuclear features.

Diagnostic question

How should this be categorised and what is the implied management?

Reveal differential diagnosis
  • Adenomatoid nodule
  • Papillary thyroid carcinoma, follicular variant
  • Hyperplastic nodule
Reveal final diagnosis

Follicular neoplasm (Bethesda category IV)

Learning points

  • Bethesda IV implies a defined risk of malignancy
  • Cytology cannot distinguish follicular adenoma from carcinoma
  • Molecular testing may refine risk

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