Blood bone marrow in a process called hematopoiesis, which includes erythropoiesis, the production of red blood cells; and myelopoiesis, the production of white blood cells and platelets. During childhood, almost every human bone produces red blood cells; as adults, red blood cell production is limited to the larger bones: the bodies of the vertebrae, the breastbone (sternum), the ribcage, the pelvic bones, and the bones of the upper arms and legs. In addition, during childhood, the thymus gland, found in the mediastinum, is an important source of T lymphocytes. The proteinaceous component of blood (including clotting proteins) is produced predominantly by
Alveolar soft part sarcoma will ultimately form the gut. Malignancies arising from cells that were originally part of the outer layer of the sphere and those that were part of the embryonic tunnel are termed carcinomas; malignancies arising from the cells between the outer layer and the inner burrow are termed sarcomas.) Typically, ASPS arises in muscles and deep soft tissue of the thigh or the leg (lower extremities), but can also appear in the upper extremities (hands, neck, and head). While ASPS is a soft tissue sarcoma, it can also spread and grow inside the bones. The term alveolar comes from the microscopic