A 45-year-old woman who underwent hemithyroidectomy two years ago for minimally invasive follicular carcinoma now presents with pathological fracture of a lumbar vertebra. Biopsy of the vertebral lesion shows well-differentiated thyroid follicles that take up radioiodine. This behaviour reflects which characteristic of follicular carcinoma?

• A Seeding along needle biopsy tracks
• B Predictable lymphatic spread to pretracheal nodes first
• C Direct invasion of the vertebral column through Berry's ligament
• D Predominantly haematogenous dissemination with early bone and lung metastases ✓

Explanation

Follicular carcinoma characteristically invades vessels rather than lymphatics, so distant metastases to bone and lung occur while cervical nodes are spared. Bone metastases are typically osteolytic, may retain radioiodine avidity, and often produce pathological fractures or spinal cord compression years after diagnosis. This contrasts sharply with papillary carcinoma, which spreads primarily to regional lymph nodes and rarely metastasises haematogenously at presentation.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.