McGill thyroid nodule score

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The McGill thyroid nodule score (MTNS) is a scoring system developed to estimate the risk of malignancy of thyroid nodules .

Scoring system

The MTNS is based on 22 parameters:

  • eight clinical or laboratory parameters
    • gender (male): 1 point
    • age (>45 years old): 1 point
    • palpable nodule (present): 1 point
    • TSH level (>1,4 mIU/L): 1 point
    • consistency (stone/bone hard):  2 points
    • ionizing radiation exposure: 3 points
    • family history of thyroid cancer: 3 points
    • ethnicity (Hawaiian, Filipino, Icelandic): 3 points
  • eight imaging findings
    • hypoechoic nodule: 1 point
    • increased vascularity at color Doppler: 1 point
    • shape (taller than wide): 1 point
    • calcifications
      • coarse calcifications: 1 point
      • microcalcifications: 2 points
    • enlarging
      • >10%: 1 point
      • >30%: 2 points
    • lymphadenopathy (present): 2 points
    • size
      • 2.0-2.9 cm: 2 points
      • 3.0-3.9 cm: 3 points
      • 4 cm or greater: 4 points
    • PET scan focally positive: 4 points
  • six cytological or molecular results
    • Hürthle cell lesion (present): 2 points
    • favor neoplasm (present): 3 points
    • atypia (non reactive) 
      • mild: 3 points
      • moderate: 4 points
      • severe: 5 points
    • suspicious for malignancy (present): 7 points
    • HBME-1 (positive): 7 points
    • BRAF mutation (present): 7 points
Score Interpretation and percentage of risk of malignancy
  • 0 point = 0% 
  • 1-3 points = 27%
  • 4-7 points = 32%
  • 8 points = 39%
  • 9-11 points = 63%
  • 12-13 points = 88%
  • 14-18 points = 93%
  • >18 points = 100%

Practical points

Some think the McGill Thyroid Nodule Score is useful when the result of FNA is indeterminate.

The "mild", "moderate", and "severe" classification refer to subclassifications within the Bethesda 3 category. This is not always available on pathology reports.