What is papillary thyroid carcinoma?

75-85%, 20-40, most often linked to exposure to ionizing radiation. Macroscopy solitary or multifocal lesion, encapsulated/cyst/heterogenous, more often infiltrating stellar irregular outline, firm consistency whitish granular appearance. Microscopy fibrovasclar stalk covered by cuboidal epithelium, mostly well-differentiated and orderly epithelium, but may be sometimes more anaplastic/pleonorphic. Papillary architecture (not always seen), ground glass nuclei, cytoplasmic invagination making intranuclear inclusion appearance which are sufficient in dx of papillary carcinoma. Psammoma bodies present in lesion pathogneumonic for Papillary carcicinoma Often lymph invasion occurs (50%) but uncommon vascular invasion alot of variants most common is encapsulated follicular variant