5-Minute Pediatric Consult

Abdominal Mass


An unusually enlarged abdominal or retroperitoneal organ (i.e., hepatomegaly, splenomegaly, or enlarged kidney) or a defined fullness in the abdominal cavity not directly associated with an abdominal organ


  • 60% of abdominal masses in children are due to organomegaly
  • 40% of abdominal masses in children are due to anomalies of development, neoplasms, or inflammatory conditions


  • Phase 1: Determine the location of the abdominal mass and its association with intra-abdominal organs via a thorough and careful abdominal examination.
  • Phase 2: Perform diagnostic tests:
    • Ultrasound is the most efficient way to start the evaluation.
  • Clinical pearls:
    • In neonates, a palpable liver edge can be normal; the total liver span is most important.
    • In infants, a full bladder is often mistaken for an abdominal mass.
    • In infants, most abdominal masses are of renal origin and nonmalignant.
    • Severe constipation in older children and adolescents can present as a large, hard mass extending from the pubis past the umbilicus.
    • Gastric distention should be considered in all children who present with a tympanitic epigastric mass.

Signs and Symptoms


  • Weight loss:
    • Tumor, inflammatory bowel disease
  • Fever:
    • Abscess, malignancy
  • Jaundice:
    • Liver/biliary disease
  • Hematuria or dysuria:
    • Renal disease
  • Vomiting:
    • Intestinal obstruction
  • Frequency and quality of bowel movements:
    • Constipation, intussusception, compression of bowel by mass
  • Bleeding or bruising:
    • Coagulopathy
  • History of abdominal trauma:
    • Pancreatic pseudocyst, duodenal hematoma
  • Sexual activity:
    • Pregnancy
  • Age of patient:
    • Often a helpful clue in investigating the cause of the abdominal mass
    • In neonates, the most common origin of abdominal masses is the genitourinary system (cystic kidney disease, hydronephrosis).
    • In infants and preschool-aged children, the most common malignant tumors are Wilms tumor and neuroblastoma.
    • In adolescent-aged girls, ovarian disorders, hematocolpos, and pregnancy are more common causes of abdominal masses.

Physical Exam
  • General appearance:
    • Ill-appearance or cachexia point toward infection or malignancy.
  • Location of abdominal mass helps to narrow differential diagnosis:
    • Left lower quadrant: Constipation, ovarian process, ectopic pregnancy
    • Left upper quadrant: Anomaly of the kidney or splenomegaly
    • Right lower quadrant: Abscess (inflammatory bowel disease), intestinal phlegmon, appendicitis, intussusception, ovarian process, ectopic pregnancy
    • Right upper quadrant: Involves 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)
  • Characteristics of abdominal mass:
    • Mobility, tenderness, firmness, smoothness, and/or irregularity of the surface of the mass can provide clues to its significance.
  • Hard and immobile mass:
    • Tumor
  • Extension of mass across midline or into pelvis:
    • Tumor, hepatomegaly, splenomegaly
  • Percussion of mass:
    • Dullness indicates a solid mass, tympany indicates a hollow viscus.
  • Shifting dullness, fluid wave:
    • Ascites
  • Skin exam:
    • 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.
  • Lymphadenopathy or lymphadenitis:
    • Systemic process either malignant or infectious



  • CBC:
    • Anemia or hemolysis
  • Chemistry panel:
    • 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
  • Uric acid and lactate dehydrogenase levels:
    • Elevated in the setting of rapid cell turnover of solid tumors

  • Plain abdominal radiographs:
    • Rule out intestinal obstruction, identify calcifications, fecal impaction.
  • Abdominal ultrasound:
    • Can usually identify the origin of the mass and differentiate between solid and cystic tissue; disadvantages are operator variability and a limited exam when bowel gas obscures underlying abdominal tissues.
  • CT scan:
    • Can provide more detail when there is overlying gas or bone; if malignancy is suspected should do chest, abdomen, and pelvis CT
  • Magnetic resonance imaging:
    • Vascular lesions of liver, major vessels, and tumors
  • Radioisotope cholescintigraphy (HIDA) scan:
    • Liver, gallbladder
  • Voiding cystourethrography or intravenous urography:
    • Wilms tumor, cystic kidney disease, posterior urethral valves, hydronephrosis
  • Upper GI study and barium enema:
    • May be of benefit when the mass involves the intestine

Differential Diagnosis

  • Stomach:
    • Gastroparesis
    • Duplication
    • Foreign body/bezoar
    • Gastric torsion
    • Gastric tumor (lymphoma, sarcoma)
  • Intestine:
    • Feces (constipation)
    • Meconium ileus
    • Duplication
    • Volvulus
    • Intussusception
    • Intestinal atresia or stenosis
    • Malrotation
    • Inflammatory bowel disease complications (abscess, phlegmon)
    • Appendiceal or Meckel diverticulum abscess
    • Toxic megacolon
    • Lymphoma, adenocarcinoma
    • Carcinoid
    • Foreign body
    • Duodenal hematoma (trauma)
  • Liver:
    • Hepatomegaly due to intrinsic liver disease:
      • Hepatitis (viral, autoimmune)
      • Metabolic disorders (Wilson disease, glycogen storage disease)
      • Congenital hepatic fibrosis
    • Cystic disease (Caroli disease)
    • Tumor (hepatic adenoma, hepatoblastoma, hepatocellular carcinoma or diffuse neoplastic process such as lymphoma)
    • Vascular tumor (hamartoma, hemangioma, hemangioendothelioma)
    • Vascular obstruction/congestion (Budd-Chiari syndrome, CHF)
    • Focal nodular hyperplasia
  • Spleen:
    • Storage disease (Gaucher, Niemann-Pick)
    • Langerhans cell histiocytosis
    • Leukemia
    • Hematologic (hemolytic disease, sickle cell disease, hereditary spherocytosis/elliptocytosis)
    • Wandering spleen
  • Pancreas:
    • Pseudocyst (trauma)
    • Pancreatoblastoma
  • Gallbladder/Biliary tract:
    • Choledochal cyst
    • Hydrops
    • Obstruction (stone, stricture, trauma)
  • Kidney:
    • Multicystic dysplastic kidney
    • Hydronephrosis/ureteropelvic obstruction
    • Polycystic disease
    • Wilms tumor
    • Renal vein thrombosis
    • Cystic nephroma
    • Mesoblastic nephroma
  • Bladder:
    • Posterior urethral valves
    • Neurogenic bladder
  • Adrenal:
    • Adrenal hemorrhage
    • Adrenal abscess
    • Neuroblastoma
    • Pheochromocytoma
  • Uterus:
    • Pregnancy
    • Hematocolpos
    • Hydrometrocolpos
  • Ovary:
    • Cysts (dermoid, follicular)
    • Torsion
    • Germ cell tumor
  • Peritoneal:
    • Ascites
    • Teratoma
  • Abdominal wall:
    • Umbilical/inguinal/ventral hernia
    • Omphalocele/gastroschisis
    • Trauma (rectus hematoma)
    • Tumor (fibroma, lipoma, rhabdomyosarcoma)
  • Omentum/Mesentery:
    • Cysts
    • Mesenteric fibromatosis
    • Tumors (liposarcoma, leiomyosarcoma, fibrosarcoma, mesothelioma)
  • Other:
    • Lymphangioma
    • Fetus in fetu
    • Sacrococcygeal teratoma

General Measures

  • Immediate hospitalization for patients who present with an abdominal mass and signs and/or symptoms of intestinal obstruction
  • Initial diagnostic studies should include an abdominal ultrasound and a surgical or oncological consultation as indicated.
  • The remaining causes of abdominal masses require urgent care and timely evaluation and referral to appropriate specialists.


Surgical consultation is often necessary in the early stages of evaluation and management of an abdominal mass, emergently if there is concern for intestinal or biliary obstruction.


Admission Criteria

  • Immediate hospitalization for patients who present with an abdominal mass and signs and/or symptoms of intestinal obstruction (intussusception, volvulus, gastric torsion, bezoar, foreign body):
    • Toxic megacolon
    • Ovarian torsion
    • Ectopic pregnancy
    • Biliary obstruction (stone, hydrops)
    • Fever
    • Pancreatitis (pseudocyst)
  • 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 requires immediate attention, and diagnostic studies should be performed expeditiously at a facility capable of diagnosing pediatric disorders.


  • 789.3 Abdominal or pelvic swelling, mass, or lump


  1. Chandler JC, Gauderer MWL. The neonate with an abdominal mass. Pediatr Clin North Am. 2004;51:979–997.  [PMID:15275984]
  2. Golden CB, Feusner JH. Malignant abdominal masses in children: Quick guide to evaluation and diagnosis. Pediatr Clin North Am. 2002;49:1369–1392.  [PMID:12580370]
  3. Mahaffey SM, Rychman RC, Martin LW. Clinical aspects of abdominal masses in children. Semin Roentgenol. 1988;23:161–174.  [PMID:3045973]
  4. Merten DF, Kirks DR. Diagnostic imaging of pediatric abdominal masses. Pediatr Clin North Am. 1985;32:1397–1426.  [PMID:2999684]


Rose C. Graham-Maar, MD, MSCE

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