Which of the following type of thyroid cancer metastasize to the bone MOST commonly?
Papillary cancer spreads mainly by lymphatic route. Anaplastic thyroid carcinoma by direct (anaplastic cancer is characterized by extensive local invasion) Follicular spreads mainly by hematogenous route (to lung, bones and CNS) So bone metastasis is common in follicular cancer In follicular carcinoma, huhle cell carcinoma (a subtype of follicular carcinoma) is more invasive and metastasize more frequently to bones. Bony metastasis from thyroid is osteolytic. Ref: Harrison 14/e Page 2031.
Follicular
Papillary
Huhle cell tumor
Anaplastic