Abstract
Simultaneous occurrence of papillary and follicular thyroid cancer, known as differentiated thyroid cancer, has been reported with various presentations, but presence of an anaplastic cancer, as an undifferentiated cancer, in addition to differentiated thyroid cancer is rarely reported. We here report a 40-year-old man with papillary thyroid cancer on his right thyroid lobe and metastasized to the right posterior triangle of the neck. Survey on the mass in the right posterior triangle revealed presence of simultaneous papillary, follicular, and anaplastic thyroid cancer. The patient underwent right thyroid lobectomy and he received adjuvant radiotherapy in combination with chemotherapy.