Which of the following tumors characteristically spreads by lymphatics?
High-Yield Explanation
Papillary cancer of the thyroid characteristically spreads by lymphatics, rather than by vessel invasion.Dissemination of tumor occurs by seeding within body cavities, lymphatic spread, or hematogenous spread. Seeding is commonly seen with colorectal cancers and ovarian cancers. Lymphatic invasion is more common in carcinomas than sarcomas. Lymphatic spread initially goes to the regional lymph nodes (subcapsular sinus is the first site), and from there into the systemic circulation the thoracic duct. Hematogenous spread is ored by sarcomas (not exclusively), with spread to the lungs and liver a common finding. Carcinomas with a propensity for hematogenous invasion are: renal adenocarcinomas invading the renal vein, hepatocellular carcinomas invading the hepatic and poal veins, and follicular carcinomas of the thyroid, which commonly bypass the cervical lymph nodes and metastasize to the lungs and bone.