An abdominal mass is any localized enlargement or swelling in the human abdomen. Depending on its location, the abdominal mass may be caused by an enlarged liver (hepatomegaly), enlarged spleen (splenomegaly), protruding kidney, a pancreatic mass, a retroperitoneal mass (a mass in the posterior of the peritoneum), an abdominal aortic aneurysm, or various tumours, such as those caused by abdominal carcinomatosis and omental metastasis. The treatments depend on the cause, and may range from watchful waiting to radical surgery.

Features

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Many abdominal masses are discovered incidentally during routine physical examination. When they present symptomatically, abdominal masses are most frequently associated with pain or digestive problems. However, depending on the cause, masses may be associated with other signs and symptoms, such as jaundice or bowel obstruction.

Diagnosis

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The first steps in diagnosis are a medical history and physical examination. Important clues during history include weight loss, diarrhea and abdominal pain.

During physical examination, the clinician must identify the location of the mass, as well as characterize its location (usually specified in terms of quadrants). The mass should be assessed for whether it is rigid or mobile. It should also be characterized for pulse or peristalsis, as these would help in further identifying the mass.

Routine blood tests are usually the next step in diagnosis after a thorough medical history and physical examination. They should include a full blood count, blood urea nitrogen (BUN), creatinine, and liver function tests such as albumin, international normalized ratio (INR), partial thromboplastin time (PTT), serum amylase and total bilirubin (TBIL). If late-stage liver disease is suspected, then a serum glucose may be appropriate.

Common causes

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• Abdominal aortic aneurysm
• Bladder distention
• Cholecystitis (an inflammation of the gallbladder)
• Colon cancer
• Crohn's disease
• Bowel obstruction
• Diverticulitis
• Gallbladder tumor
• Hydronephrosis (fluid-filled kidney)
• Kidney cancer (including renal cell carcinoma)
• Liver cancer
• Hepatomegaly (Liver enlargement)
• Neuroblastoma
• Ovarian cyst
• Pancreatic abscess
• Pancreatic pseudocyst
• Splenomegaly (Spleen enlargement)
• Stomach cancer
• Uterine leiomyoma (fibroids)
• Volvulus (twisted piece of the gastrointestinal tract)
• Ureteropelvic junction obstruction

References

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• MedlinePlus medical encyclopedia: Abdominal mass - An informative primer on abdominal masses and their common causes.
• First Principles of Gastroenterology: Abdominal Mass - This chapter discusses the basic approach to abdominal masses.

Medical signs