Abdominal Mass, Pediatric

Basics

Description

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

Epidemiology

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).

Diagnosis

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 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.

History

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; caf © 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 & 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

Imaging

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

Treatment

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

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

Codes

ICD09

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 Hirschsprungs
777.1 Meconium obstruction in fetus or newborn
564.00 Constipation, unspecified

ICD10

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

SNOMED

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)

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