Sectioning through a lobe of excised thyroid gland reveals a papillary carcinoma. This neoplasm can be multifocal, as seen here, because of the propensity of this neoplasm to invade lymphatics within thyroid, and lymph node metastases are also common. The larger mass shown here is cystic and contains papillary excresences. These tumors most often arise in middle-aged women. [Image contributed by John Nicholls, MD, Hong Kong University]