Which four carcinomas are known to spread hematogenously?

Hematogenous spread refers to the dissemination of cancer cells through the bloodstream, allowing them to establish secondary tumors in distant sites. Follicular thyroid carcinoma, choriocarcinoma, renal cell carcinoma, and hepatocellular carcinoma are indeed known for their tendency to spread in this manner.

Follicular thyroid carcinoma is capable of invading blood vessels and can metastasize to distant organs, particularly the lungs and bones. Choriocarcinoma, a type of trophoblastic tumor, is notorious for its rapid vascular spread, often leading to metastases in the lungs and brain. Renal cell carcinoma is known to spread hematogenously; it can also invade renal veins and spread to distant sites like the lungs. Hepatocellular carcinoma commonly invades the hepatic venous system and can also metastasize via the bloodstream.

In examining the other choices, they include some carcinomas that may spread through different mechanisms or are less associated with hematogenous spread. For instance, while small cell lung cancer can spread hematogenously, it is not universally recognized as a characteristic of all lung cancers, unlike the options in the correct answer. Other choices, such as pancreatic cancer, may exhibit local invasion more than hematogenous spread, depending on the specific