A palpable lesion or fullness in the abdominal cavity which may or may not be related to abdominal viscera; the mass may be abdominal or retroperitoneal in origin


  • Etiologies for abdominal masses are varied and the differential depends on age and anatomic location.
  • Majority are nonsurgical in nature; many are associated with constipation.
  • Approximately 57% of abdominal masses in children are due to organomegaly (hepatomegaly or splenomegaly).


  • Stomach
    • Gastric distension or gastroparesis
    • Duplication
    • Foreign body or bezoar
    • Gastric torsion
    • Gastric tumor (lymphoma, sarcoma)
  • Intestine
    • Feces (constipation)
    • Intestinal distension or toxic megacolon
    • Foreign body
    • Meconium ileus
    • Duplication
    • Volvulus
    • Intussusception
    • Intestinal atresia or stenosis
    • Malrotation
    • Complications of inflammatory bowel disease (abscess, phlegmon)
    • Appendiceal inflammation
    • Meckel diverticulum or abscess
    • Duodenal hematoma (trauma)
    • Lymphoma, adenocarcinoma, GI stromal tumor
    • Carcinoid (appendiceal)
  • Liver
    • Hepatomegaly due to intrinsic liver disease
      • Hepatitis (e.g., infectious, autoimmune)
      • Metabolic or storage disorders (e.g., Wilson disease, glycogen storage disease)
      • Infiltration of liver (cyst, tumors)
      • Biliary obstruction
      • Vascular obstruction/impaired venous congestion (Budd-Chiari syndrome, congestive heart failure)
    • Cystic disease (e.g., Caroli disease)
    • Solid tumor (hepatoblastoma; hepatocellular carcinoma; hepatic adenoma; or other diffuse, systemic, neoplastic process)
    • Vascular tumor (hemangioma or hemangioendothelioma)
    • Other: hamartomas, focal nodular hyperplasia
  • Gallbladder/biliary tract
    • Choledochal cyst
    • Hydrops of gallbladder
    • Obstruction (stone, stricture, trauma)
  • Spleen
    • Congenital cysts
    • Storage disease (e.g., Gaucher, Niemann-Pick)
    • Langerhans cell histiocytosis
    • Leukemia
    • Hematologic (hemolytic disease [e.g., sickle cell] or other RBC disorders [e.g., hereditary spherocytosis])
    • Portal hypertension
    • Wandering spleen
  • Pancreas
    • Congenital cysts
    • Pseudocyst (trauma, pancreatitis)
    • Pancreatoblastoma
    • Neuroendocrine tumors (insulinomas, gastrinomas)
    • Solid and papillary epithelial neoplasms
  • Kidney
    • Hydronephrosis or ureteropelvic obstruction
    • Multicystic dysplastic kidney
    • Polycystic disease
    • Tumor (mesoblastic nephroma, Wilms tumor, renal cell carcinoma)
    • Renal vein thrombosis
    • Cystic nephroma
  • Bladder
    • Bladder distension
    • Neurogenic bladder
  • Adrenal
    • Adrenal hemorrhage
    • Adrenal abscess
    • Neuroblastoma
    • Pheochromocytoma
  • Uterus
    • Pregnancy
    • Hematocolpos
    • Hydrocolpos or hydrometrocolpos
  • Ovary
    • Cysts (dermoid, follicular)
    • Torsion
    • Germ cell tumor
  • Peritoneal
    • Ascites
    • Teratoma
  • Abdominal wall
    • Umbilical/inguinal/ventral hernia
    • Omphalocele/gastroschisis
    • Urachal cyst
    • Trauma (rectus hematoma)
    • Tumor (fibroma, lipoma, rhabdomyosarcoma)
  • Omentum/mesentery
    • Cysts
    • Mesenteric fibromatosis
    • Mesenteric adenitis
  • Other
    • Tumors (liposarcoma, leiomyosarcoma, fibrosarcoma, mesothelioma)
    • Intra-abdominal testicle (torsion)
    • Lymphangioma
    • Fetus in fetu
    • Sacrococcygeal teratoma

Approach to the Patient

When evaluating a pediatric abdominal mass, an organized approach is critical:

  • Phase 1: Perform a careful clinical history and abdominal examination in order to help assess clinical symptoms, duration of symptoms, and approximate anatomic location of the mass.
  • Phase 2: Perform diagnostic tests:
    • Obtain abdominal x-ray to assess for bowel obstruction, fecal load, or mass effect; obtain ultrasound to identify organ of origin and tissue components (e.g., cystic, hemorrhage, etc.).
    • Laboratory testing as indicated
  • Hints for screening problems
    • Constipation and fecal impaction can present as a large, hard mass extending from the pubis.
    • In neonates, a palpable liver edge can be normal; assess the total liver span.
    • In infants, a full bladder is often mistaken for an abdominal mass.
    • Certain genetic disorders/syndromes are associated with increased risk of tumor development (e.g., Beckwith-Wiedemann syndrome and Wilms tumor).
    • Gastric distention should be considered in all children who present with a tympanitic epigastric mass.


  • Question: Weight loss?
  • Significance: Malignancy, inflammatory bowel disease
  • Question: Fever?
  • Significance: Infection, malignancy
  • Question: Jaundice?
  • Significance: Hepatobiliary or hematologic disease
  • Question: Hematuria or dysuria?
  • Significance: Renal disease
  • Question: Vomiting, bilious vomiting, or early satiety?
  • Significance: Intestinal obstruction
  • Question: Abdominal pain?
  • Significance: Appendicitis, intussusception, intestinal obstruction
  • Question: Frequency and quality of bowel movements?
  • Significance: Constipation, intussusception, compression of bowel by mass
  • Question: Bleeding or bruising?
  • Significance: Liver disease, coagulopathy
  • Question: Pallor or weakness?
  • Significance: Sign of anemia or blood loss
  • Question: History of abdominal trauma?
  • Significance: Pancreatic pseudocyst, duodenal hematoma
  • Question: Sexual activity?
  • Significance: Pregnancy
  • Question: Age of patient?
  • Significance:
    • In neonates, the most common origin of abdominal masses are genitourinary (cystic kidney disease, hydronephrosis).
    • In adolescent-aged girls, ovarian disorders, hematocolpos, and pregnancy should be considered.
    • Most common malignant abdominal tumors by age: (1) infants: neuroblastoma, Wilms tumor; (2) children: Wilms tumor, sarcomas, germ cell tumors, (3) children >10 years of age: sarcomas, germ cell tumors, and abdominal lymphomas

Physical Exam

  • Finding: General appearance?
  • Significance: Ill appearance or cachexia point toward infection or malignancy.
  • Finding: Location of abdominal mass?
  • Significance:
    • Left lower quadrant: feces, ovarian process, ectopic pregnancy
    • Left upper quadrant: splenomegaly, anomaly of the kidney
    • Right lower quadrant: abscess (inflammatory bowel disease), intestinal phlegmon, appendicitis, intussusception, ovarian process, ectopic pregnancy
    • Right upper quadrant: liver, gallbladder, biliary tree, or intestine
    • Epigastric: abnormality of the stomach (bezoar, torsion), pancreas (pseudocyst), or enlarged liver
    • Suprapubic: pregnancy, hydrometrocolpos, hematocolpos, posterior urethral valves
    • Flank: renal disease (cystic kidney, hydronephrosis, Wilms tumor)
  • Finding: Characteristics of abdominal mass?
  • Significance: Mobility, tenderness, firmness, smoothness, and/or irregularity of the surface of the mass can provide clues to its significance.
  • Finding: Hard and immobile mass?
  • Significance: Tumor
  • Finding: Extension of mass across midline or into pelvis?
  • Significance: Tumor, hepatomegaly, splenomegaly
  • Finding: Percussion of mass?
  • Significance: Dullness indicates a solid mass; tympany indicates a hollow organ.
  • Finding: Shifting dullness, fluid wave?
  • Significance: Ascites
  • Finding: Skin exam?
  • Significance: Bruising and petechiae may occur with coagulopathy related to liver disease and malignant infiltration of bone marrow; café au lait spots are associated with neurofibromas.
  • Finding: Lymphadenopathy or lymphadenitis?
  • Significance: Systemic process either malignant or infectious
  • Finding: Peritoneal signs?
  • Significance: Appendicitis, bowel obstruction or perforation; indication for urgent surgical consultation
  • Finding: Rectal bleeding?
  • Significance: Intestinal inflammation, polyp, or other bleeding lesion

Diagnostic Tests and Interpretation

  • Test: CBC with differential
  • Significance: Anemia, hemolysis
  • Test: Chemistry panel
  • Significance:
    • Renal disease: BUN and creatinine levels
    • Liver disease (bilirubin, ALT, AST, alkaline phosphatase, GGT, albumin, PT/PTT)
    • Gallbladder disease (bilirubin, GGT)
    • Pancreatic disease: amylase/lipase levels
    • Intestinal disease: hypoalbuminemia
  • Test: Uric acid and lactate dehydrogenase levels
  • Significance: Elevated in the setting of rapid cell turnover of solid tumors
  • Test: Serum quantitative beta-human chorionic gonadotropin (hCG)
  • Significance: Pregnancy, germ cell tumor


  • Plain radiographs
    • Evaluate for intestinal obstruction (dilated bowel loops, air fluid levels), bowel gas pattern, calcifications, or fecal impaction; urinary retention
  • Ultrasound
    • Can identify the origin of the mass and differentiate between solid and cystic tissue; Doppler ability can help assess vascularity. Disadvantage is operator variability, and visualization may be limited by overlying bowel gas.
  • CT scan
    • Can provide more detail when there is overlying gas or bone; if malignancy is suspected, should also do chest in addition to abdomen and pelvis
  • MRI
    • Vascular lesions of liver, major vessels, and tumors
  • Nuclear medicine
    • Radioisotope cholescintigraphy (HIDA) scan of liver, gallbladder/biliary tree
    • Meckel scan: can identify gastric mucosa contained within a Meckel diverticulum or intestinal duplication
    • Intravenous urography to assess renal system
  • Fluoroscopy
    • Upper GI studies and barium enema studies: may be of benefit when the mass involves the intestine
    • Voiding cystourethrography (VCUG) to assess renal system


General Measures

  • Immediate hospitalization for patients who present with an abdominal mass and/or signs of dehydration, intestinal obstruction, bleeding, feeding intolerance, or clinical decompensation
  • In addition to initial diagnostic and laboratory testing, a pediatric surgical or oncologic consultation should be obtained as indicated.
  • The remaining causes of abdominal masses require urgent care and timely evaluation and referral to appropriate specialists.

Issues for Referral

Except for the diagnosis of constipation, the presence of an abdominal mass in children requires immediate attention, and diagnostic studies should be performed expeditiously at a pediatric health care facility.

Admission Criteria

  • Immediate hospitalization for patients who present with an abdominal mass and signs and/or symptoms of intestinal obstruction, distension, or peritoneal symptoms (intussusception, volvulus, gastric torsion, bezoar, foreign body, appendicitis)
    • Toxic megacolon
    • Ovarian torsion
    • Ectopic pregnancy
    • Biliary obstruction (stone, hydrops)
    • Fever
    • Anemia, coagulopathy
    • Pancreatitis (pseudocyst)
  • The remaining causes of abdominal masses require urgent care and timely evaluation and referral to appropriate specialists.

Additional Reading

  1. Chandler JC, Gauderer MWL. The neonate with an abdominal mass. Pediatr Clin North Am. 2004;51(4):979–997.  [PMID:15275984]
  2. Golden CB, Feusner JH. Malignant abdominal masses in children: quick guide to evaluation and diagnosis. Pediatr Clin North Am. 2002;49(6):1369–1392.  [PMID:12580370]
  3. Ladino-Torres MF, Strouse PJ. Gastrointestinal tumors in children. Radiol Clin North Am. 2011;49(4):665–677.  [PMID:21807167]
  4. Stevenson RJ. Abdominal masses. Surg Clin North Am. 1985;65(6):1481–1504.  [PMID:3000009]



  • 789.30 Abdominal or pelvic swelling, mass, or lump, unspecified site
  • 789.1 Hepatomegaly
  • 789.2 Splenomegaly
  • 787.3 Flatulence, eructation, and gas pain
  • 564.7 Megacolon, other than Hirschsprung's
  • 777.1 Meconium obstruction in fetus or newborn
  • 564.00 Constipation, unspecified


  • R19.00 Intra-abd and pelvic swelling, mass and lump, unsp site
  • R16.0 Hepatomegaly, not elsewhere classified
  • R16.1 Splenomegaly, not elsewhere classified
  • R14.0 Abdominal distension (gaseous)
  • K59.3 Megacolon, not elsewhere classified
  • K59.00 Constipation, unspecified
  • P76.0 Meconium plug syndrome


  • 274719002 Intra-abdominal and pelvic swelling, mass and lump (finding)
  • 80515008 Large liver (disorder)
  • 16294009 Splenomegaly (disorder)
  • 271835004 abdominal distension, gaseous (finding)
  • 206523001 Meconium ileus (disorder)
  • 14760008 Constipation (disorder)
  • 28536002 Toxic megacolon (disorder)


Maireade E. McSweeney

Rose C. Graham

© Wolters Kluwer Health Lippincott Williams & Wilkins

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