What diagnosis refers to a tumor or swelling resulting from an injury that pools blood outside of vessels?

The diagnosis that refers to a tumor or swelling resulting from an injury that pools blood outside of vessels is a hematoma. A hematoma occurs when blood vessels are damaged, leading to the escape of blood into surrounding tissues. This accumulation of blood creates a localized swelling, which can often be felt as a firm lump under the skin. The process is usually the result of trauma, such as a fall or a blow, where blood collects in a cavity or space, rather than remaining confined within the blood vessels.

Other terms listed in the choices refer to different conditions. Hodgkin's Disease is a type of lymphoma, a cancer affecting the lymphatic system, while immunodeficiency pertains to conditions where the immune system's ability to fight infections is compromised. Gas gangrene refers to a serious bacterial infection that produces gas within tissues, often associated with trauma or surgical wounds. Understanding these distinctions highlights the specific nature of a hematoma in relation to trauma-induced blood pooling.