Papillary Carcinoma.

previous exposure to ionizing radiation

they may be well circumscribed and even encapsulated; in other instances, they infiltrate the adjacent parenchyma with ill-defined margins

areas of fibrosis and calcification and are often cystic

Gross papillary foci may be present

Unlike hyperplastic papillary lesions, the neoplastic papillae have dense fibrovascular cores. Concentrically calcified structures termed psammoma bodies are often present within the papillae

nuclear features even in the absence of a papillary architecture are diagnostic of papillary Ca- finely dispersed chromatin, which imparts an optically clear appearance, giving rise to the designation "ground-glass" or "Orphan Annie eye" nuclei

Invaginations of the cytoplasm may give the appearance of intranuclear inclusions (hence the term pseudo-inclusions)

Metastases to adjacent cervical lymph nodes common- might be the only presentation of the neoplasm.