What type of benign tumor consists of newly formed blood vessels?

A hemangioma is a type of benign tumor that specifically arises from an overgrowth of blood vessels. This condition is characterized by the proliferation of vascular endothelial cells, leading to the formation of a mass that appears red or purple due to the numerous blood vessels within it. Hemangiomas can occur in any part of the body but are most commonly found on the skin or in internal organs.

The appearance and characteristics of a hemangioma can vary significantly; they might be flat or raised and can change in size and shape over time. Often, these tumors are harmless and may even resolve on their own without treatment as the individual ages.

In contrast, other options such as neoplasms refer generally to any new and abnormal growth of tissue which may include both benign and malignant tumors, including but not limited to hemangiomas. Cysts are fluid-filled sacs that can form within tissues but do not arise from blood vessel growth. A lipoma, on the other hand, is a benign tumor composed of adipose (fat) tissue, which is distinct from the vascular nature of hemangiomas. Thus, the defining characteristic of hemangiomas as tumors formed from blood vessels makes it the correct answer.