The abdomen in vertebrates contains a number of organs belonging to, for instance, the digestive system, urinary system, and muscular system. Contents
The abdominal cavity contains most organs of the digestive system, including the stomach, the small intestine, and the colon with its attached appendix. Other digestive organs are known as the accessory digestive organs and include the liver, its attached gallbladder, and the pancreas, and these communicate with the rest of the system via various ducts. The spleen, and organs of the urinary system including the kidneys, and adrenal glands also lie within the abdomen, along with many blood vessels including the aorta and inferior vena cava. The urinary bladder, uterus, fallopian tubes, and ovaries may be seen as either abdominal organs or as pelvic organs. Finally, the abdomen contains an extensive membrane called the peritoneum. A fold of peritoneum may completely cover certain organs, whereas it may cover only one side of organs that usually lie closer to the abdominal wall. This is called the retroperitoneum, and the kidneys and ureters are known as retroperitoneal organs. Abdominal organs can be highly specialized in some animals. For example, the stomach of ruminants, (a suborder of mammals that includes cattle and sheep), is divided into four chambers – rumen, reticulum, omasum and abomasum. Muscles
There are three layers of muscles in the abdominal wall. They are, from the outside to the inside: external oblique, internal oblique, and transverse abdominal.
Lipoblastoma is a type of rare, subcutaneous, benign, fatty tumor, found in infants, and children, more common in males with tendency of local recurrence. Local recurrence can happen in up to 80% of incompletely resected tumours. Therefore, complete surgical resection is required to prevent recurrence. It arises from embyronic white fat that is rapidly enlarging. Most common locations are at the trunk and extremities.Types include:
Benign lipoblastomatosis, a tumor, also known as an embryonic lipoma, which usually occurs in children under three years old. This is the tumor of brown fat cells. Myxoid lipoblastoma, a cutaneous condition characterized by excess mucin

Specimen
Macroscopic
Grossly, it has a pale yellow, myxoid cut surface with small cystic foci. Microscopic
It has lobules consists of immature adipose tissue separated by fibrous septa and lipoblasts at different stages of maturation, without atypia or mitosis. Plexiform capillary network and mature adipose tissue are seen at the central part of the lobule. See also
Lipoblast
Lipoma


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