Classification of thyroid neoplasms

WHO classification of thyroid tumours (1988)

I. Epithelial tumours

  • Benign
    • Follicular adenoma and variants
    • Others including hyalinizing trabecular adenoma
  • Malignant
    • Follicular carcinoma including minimally invasive, widely invasive and poorly differentiated subtypes
    • Papillary carcinoma and variants including papillary microcarcinoma, follicular variant and diffuse sclerosing variant
    • Medullary carcinoma and variants including mixed medullary-follicular carcinoma
    • Undifferentiated (anaplastic) carcinoma
    • Others

II. Non-epithelial tumours

  • Benign
  • Malignant
    • Angiosarcoma
    • Others

III. Malignant lymphomas

IV. Miscellanous tumours

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