Abdominal Mass in Children: Clinical Diagnostic Approach & Management Tool

Clinical History Assessment

Systematic approach to history taking for a child presenting with an abdominal mass

Physical Examination Guide

Systematic approach to examining a child with an abdominal mass

Diagnostic Approach

Initial Assessment

For a child presenting with a suspected or confirmed abdominal mass, the initial assessment should include:

• Detailed history focusing on symptom onset, progression, and associated symptoms
• Complete physical examination with systematic abdominal assessment
• Age-appropriate consideration of differential diagnoses
• Assessment of hemodynamic stability and need for urgent intervention

Clinical Classification of Abdominal Masses

Abdominal masses can be classified by:

Classification Parameter	Categories	Clinical Significance
Anatomic Location	Upper quadrants, lower quadrants, central, diffuse, pelvic	Guides differential diagnosis and imaging approach
Consistency	Solid, cystic, mixed	Helps narrow potential etiologies and direct imaging modality
Patient Age	Neonatal, infant, child, adolescent	Major determinant of likely diagnoses
Clinical Presentation	Symptomatic vs. incidental finding	Influences urgency of workup and management

Age-Related Differential Diagnosis

Age Group	Common Conditions	Red Flags
Neonate (0-28 days)	- Hydronephrosis - Multicystic dysplastic kidney - Ovarian cyst - Intestinal duplication - Meconium ileus/peritonitis - Neuroblastoma - Renal vein thrombosis	- Bilious vomiting - Abdominal distension - Failure to pass meconium - Jaundice with hepatomegaly - Urinary abnormalities
Infant (1-12 months)	- Intussusception - Pyloric stenosis - Wilms tumor - Neuroblastoma - Hepatoblastoma - Choledochal cyst - Hydronephrosis	- Bilious vomiting - Currant-jelly stools - Projectile vomiting - Hypertension - Weight loss - Fever
Child (1-10 years)	- Wilms tumor - Neuroblastoma - Lymphoma - Constipation - Hepatoblastoma - Appendiceal abscess - Renal cyst/hydronephrosis	- Weight loss - Night sweats - Fever - Pallor - Bone pain - Hypertension
Adolescent (>10 years)	- Ovarian mass/cyst - Lymphoma - Constipation - Appendiceal abscess - Renal cell carcinoma - Pregnancy - Inflammatory bowel disease	- Weight loss - Amenorrhea - Chronic diarrhea - Blood in stool/urine - Abdominal pain - Sexual activity

Anatomical Differential Diagnosis

Location	Potential Etiologies	Distinguishing Features
Right Upper Quadrant	- Hepatomegaly - Hepatoblastoma - Hepatic cyst/abscess - Choledochal cyst - Right hydronephrosis	- Moves with respiration - Dullness to percussion - May cross midline - Associated jaundice - Continuous with liver edge
Left Upper Quadrant	- Splenomegaly - Neuroblastoma - Adrenal mass - Left hydronephrosis - Splenic cyst/abscess	- Moves with respiration - Dullness to percussion - Cannot get above it - Associated with anemia/cytopenias - May extend toward midline
Right Lower Quadrant	- Appendiceal abscess - Intussusception - Wilms tumor - Ovarian mass/cyst (female) - Undescended testicle (male)	- Fixed vs. mobile - Associated tenderness - Relation to psoas muscle - Bowel patterns - Urinary symptoms
Left Lower Quadrant	- Constipation/fecal mass - Wilms tumor - Ovarian mass/cyst (female) - Intestinal duplication - Psoas abscess	- Indentable (stool) - Mobility characteristics - Associated with bowel habits - Relation to kidney - Pelvic extension
Central/Midline	- Intussusception - Intestinal duplication - Mesenteric cyst - Lymphoma - Urachal cyst/remnant - Distended bladder	- Relation to umbilicus - Changes with voiding - Bowel habits - Vomiting pattern - Transit across midline

Laboratory Studies

Initial laboratory evaluation may include:

Investigation	Clinical Utility	When to Consider
Complete Blood Count	Assess for anemia, infection, or malignancy	All patients with abdominal mass
Basic Metabolic Panel	Evaluate renal function and electrolyte status	All patients, particularly with suspected renal masses
Liver Function Tests	Assess hepatic involvement or biliary obstruction	Upper abdominal masses, particularly RUQ
Urinalysis/Urine Culture	Evaluate for UTI, hematuria, or renal involvement	Suspected renal or genitourinary masses
β-hCG	Rule out pregnancy in adolescent females	All postmenarchal females

Specialized Laboratory Studies

Based on suspected etiology:

Investigation	Clinical Utility	When to Consider
Alpha-fetoprotein (AFP)	Marker for hepatoblastoma, hepatocellular carcinoma, germ cell tumors	Liver mass, suspected malignancy
Urine catecholamines (VMA, HVA)	Screening for neuroblastoma	Adrenal or retroperitoneal mass
LDH	Non-specific tumor marker, elevated in lymphoma and other malignancies	Suspected malignancy, particularly lymphoma
Inflammatory markers (ESR, CRP)	Evaluate for inflammatory or infectious process	Suspected abscess or inflammatory condition
Amylase/Lipase	Assess for pancreatic involvement	Upper abdominal mass near pancreatic region

Imaging Studies

Sequential and targeted imaging approach:

Imaging Modality	Advantages	Limitations	Best Applications
Abdominal Radiograph	- Readily available - Can show calcifications - Evaluates bowel gas pattern - Detects radio-opaque foreign bodies	- Limited soft tissue contrast - Cannot characterize masses well - Radiation exposure	- Initial screening - Suspected bowel obstruction - Constipation assessment - Foreign body localization
Ultrasound	- No radiation - Excellent for cystic vs. solid distinction - Real-time imaging - No sedation required - Evaluates vascularity with Doppler	- Operator dependent - Limited by bowel gas - Restricted field of view - Poor penetration in obese patients	- First-line imaging for most pediatric masses - Pyloric stenosis - Intussusception - Kidney and bladder assessment - Ovarian pathology
CT Scan	- Excellent anatomic detail - Can image entire abdomen - Evaluates both parenchymal organs and bowel - Can guide intervention	- Radiation exposure - May require sedation in young children - IV contrast risks	- Staging for malignancy - Abscess evaluation - Trauma assessment - Complex masses requiring detailed anatomic assessment
MRI	- No radiation - Superior soft tissue contrast - Multiplanar imaging - Functional assessment capabilities	- Limited availability - Time-consuming - Usually requires sedation in young children - High cost	- Neuroblastoma - Wilms tumor - Hepatic masses - Pelvic masses - Soft tissue characterization
Nuclear Medicine Studies	- Functional information - Can detect metastases - Specific for certain tumor types	- Limited anatomic resolution - Radiation exposure - Limited availability	- MIBG scan for neuroblastoma - Bone scan for metastasis - Hepatobiliary scan for biliary disease - Renal scan for functional assessment

Diagnostic Algorithm

A stepwise approach to diagnosing abdominal masses in children:

1. Clinical assessment (history and physical examination) to localize mass and identify associated symptoms
2. Laboratory evaluation based on suspected etiology and location
3. Initial imaging: Ultrasound for most pediatric masses (non-invasive, radiation-free)
4. Secondary imaging based on ultrasound findings:
   • CT scan for detailed anatomic assessment, staging, or pre-surgical planning
   • MRI for superior soft tissue characterization, particularly for neuroblastoma, Wilms tumor, or pelvic masses
   • Nuclear medicine studies for specific tumor types or functional assessment
5. Consider biopsy if malignancy suspected and diagnosis unclear
6. Multidisciplinary discussion with pediatric surgery, oncology, radiology, and nephrology as appropriate
7. Definitive diagnosis established through combination of clinical, radiographic, and possibly histopathologic findings

Management Strategies

General Approach to Management

Key principles in managing pediatric abdominal masses:

• Age-appropriate considerations: Management varies significantly based on patient age and likely etiology
• Multidisciplinary approach: Coordination between pediatric specialists (surgery, oncology, radiology, etc.)
• Appropriate urgency: Determination of need for immediate versus planned intervention
• Family-centered care: Clear communication, emotional support, and family involvement in decision-making
• Long-term follow-up: Monitoring for complications or recurrence based on specific diagnosis

Initial Management Considerations

Clinical Scenario	Initial Management	Monitoring Parameters
Hemodynamically unstable patient	- Fluid resuscitation - Blood product administration if indicated - Urgent surgical consultation - Focused assessment with sonography (FAST)	- Vital signs q15min - Urine output - Mental status - Hemoglobin/hematocrit - Abdominal girth
Acute intestinal obstruction	- NPO status - Nasogastric tube placement - IV fluid resuscitation - Surgical consultation - Focused imaging	- Abdominal distension - Bilious output - Electrolyte balance - Serial abdominal exams
Suspected malignancy - stable	- Complete staging workup - Oncology consultation - Tissue diagnosis planning - Vascular access consideration	- Tumor markers - Pain control - Nutritional status - Psychosocial support
Incidental finding - asymptomatic	- Complete diagnostic workup - Appropriate subspecialty referral - Education and reassurance - Scheduled follow-up	- Serial imaging - Development of symptoms - Growth parameters - Quality of life

Management Based on Specific Diagnoses

Diagnosis	Management Approach	Follow-up Recommendations
Intussusception	- Air or hydrostatic reduction (first-line) - Surgical reduction if: Pneumatic/hydrostatic reduction fails Peritonitis present Perforation suspected Shock or significant illness - Address lead point if present	- Monitor for 24 hours after reduction - Follow-up within 1-2 weeks - Education about recurrence risk (10%) - Consider further workup if: Age >3 years Recurrent episodes Atypical location
Wilms Tumor	- Multidisciplinary tumor board discussion - Avoid transabdominal biopsy (risk of spillage) - Staging CT chest/abdomen/pelvis - Nephrectomy with lymph node sampling - Chemotherapy based on stage and histology - Radiation for higher stages	- Frequent follow-up during therapy - Long-term surveillance imaging - Renal function monitoring - Screening for second malignancies - Monitoring for late effects of therapy
Neuroblastoma	- Risk stratification based on age, stage, biology - Low-risk: Surgery +/- chemotherapy - Intermediate-risk: Surgery + moderate chemotherapy - High-risk: Intensive multimodal therapy: Induction chemotherapy Surgery High-dose chemotherapy with stem cell rescue Radiation Immunotherapy Differentiation therapy	- Risk-based surveillance protocols - Urine catecholamine monitoring - MIBG or other functional imaging - Developmental assessments - Monitoring for late effects
Ovarian Mass/Cyst	- Simple cysts <5cm: Observation - Cysts >5cm or complex: Consider surgery - Suspected torsion: Urgent surgical exploration - Surgical approach: Ovarian-sparing procedures when possible Minimally invasive approach preferred Tumor markers for suspicious masses	- Serial ultrasound for conservative management - Hormonal function assessment in adolescents - Follow-up after surgery in 2-4 weeks - Long-term oncologic follow-up if malignancy
Hepatic Mass	- Determination of benign vs. malignant - Hepatoblastoma: Staging, neoadjuvant chemotherapy, surgical resection - Hemangioma: Observation or propranolol for symptomatic cases - Mesenchymal hamartoma: Surgical resection - Abscess: Drainage and antibiotics	- Tumor marker monitoring (AFP) - Liver function monitoring - Serial imaging based on diagnosis - Transplant evaluation for unresectable malignancy

Surgical Considerations

Procedure Type	Indications	Special Considerations
Diagnostic Procedures	- Image-guided biopsy - Laparoscopic biopsy - Exploratory laparotomy	- Avoid transabdominal biopsy for suspected Wilms tumor - Consider risk of tumor seeding - Obtain adequate tissue for histology, molecular studies - Coordinate with pathology for proper handling
Minimally Invasive Procedures	- Cyst aspiration/fenestration - Laparoscopic mass resection - Diagnostic laparoscopy	- Patient size limitations - Conversion criteria to open procedure - Specimen retrieval techniques - Pneumoperitoneum considerations in neonates
Open Surgical Procedures	- Complex tumor resection - Large mass removal - Nephrectomy/partial nephrectomy - Hepatic resection	- Preoperative optimization - Blood product availability - ICU availability - Multidisciplinary surgical team when indicated - Special instrumentation needs
Emergent Procedures	- Perforated appendicitis with abscess - Ovarian torsion - Traumatic injury with hemorrhage - Intestinal obstruction/perforation	- Hemodynamic stabilization prior to surgery - Damage control approach when indicated - Broad-spectrum antibiotics - Staged approaches for contaminated fields

Non-Surgical Management

Appropriate for specific conditions:

Condition	Non-Surgical Approach	Monitoring Requirements
Simple renal cysts	- Observation - Serial ultrasonography	- Imaging every 6-12 months - Monitor for growth or complexity changes - Renal function assessment
Hydronephrosis (mild to moderate)	- Antibiotic prophylaxis in select cases - Serial ultrasound monitoring - Voiding cystourethrogram if indicated	- Urinalysis and culture with fevers - Renal function assessment - Imaging every a 3-6 months initially
Fecal impaction/constipation	- Bowel cleanout regimen - Maintenance laxative therapy - Dietary modification - Behavioral approaches	- Bowel diary - Regular follow-up - Adjustment of regimen based on response - Re-evaluation if no improvement
Infantile hemangioma	- Observation for asymptomatic lesions - Propranolol therapy for symptomatic lesions - Prednisolone for select cases	- Serial photographs - Cardiac monitoring with propranolol initiation - Measurement of lesion size - Assessment for ulceration or functional impairment
Small abdominal abscess	- Broad-spectrum antibiotics - Percutaneous drainage if accessible - Pain management	- Serial imaging - Inflammatory markers - Clinical assessment for improvement - Drainage output culture and quantity

Long-Term Follow-Up

• Oncologic surveillance: Protocol-based imaging and laboratory monitoring for malignant conditions
• Growth and development: Monitoring for therapy-related sequelae in children treated for malignancy
• Organ function: Regular assessment of affected organ systems (renal, hepatic, etc.)
• Psychological support: Addressing psychosocial impact of diagnosis and treatment
• Transition of care: Planning for transition to adult services for chronic conditions or cancer survivors
• Genetic counseling: For conditions with hereditary components or syndromes
• Fertility preservation: Consideration in adolescents undergoing gonadotoxic therapy

Family Education and Support

Topic	Education Points	Resources
Diagnosis Understanding	- Age-appropriate explanation of condition - Expected course and prognosis - Treatment rationale and options - Warning signs requiring medical attention	- Written materials - Diagnosis-specific websites - Anatomical models/drawings - Child life specialist consultation
Treatment Preparation	- Procedure explanations - Hospital stay expectations - Pain management approaches - Recovery timeline	- Pre-procedure tours - Procedural videos/stories - Child life preparation - Meeting with treatment team
Home Care	- Medication administration - Wound/incision care - Activity restrictions - Nutrition requirements - School accommodations	- Written discharge instructions - Demonstration and return demonstration - Follow-up phone numbers - Home health referrals when needed
Psychosocial Support	- Normal emotional responses - Sibling support - School reintegration - Coping strategies	- Social work consultation - Support groups - Psychology/psychiatry referrals - Family counseling

Quality of Life Considerations

Domain	Assessment Tools	Interventions
Physical Function	- Age-appropriate functional assessments - Pain scales - Activity diaries - Growth charts	- Physical therapy - Pain management protocols - Adaptive equipment - Nutritional support
Psychological Well-being	- Screening for anxiety/depression - Quality of life questionnaires - Body image assessment - Age-appropriate distress tools	- Psychological counseling - Art/music therapy - Support groups - Cognitive behavioral therapy
Social Integration	- School attendance/performance - Peer relationship assessment - Family functioning measures - Community participation	- School liaison services - Social skills training - Family therapy - Recreational therapy programs
Future Planning	- Career/educational aspiration assessment - Independent living skills - Health literacy evaluation - Self-advocacy skills	- Vocational counseling - Life skills training - Self-management education - Transition planning

Special Considerations

• Neonatal abdominal masses:
  • Congenital anomalies often require specialized multidisciplinary care
  • Surgical timing may be influenced by gestational age and comorbidities
  • Preoperative optimization of respiratory and nutritional status
  • Consider antenatal counseling for prenatally diagnosed conditions
• Oncologic emergencies:
  • Tumor lysis syndrome prophylaxis and management
  • Superior vena cava syndrome recognition and treatment
  • Spinal cord compression evaluation and intervention
  • Hyperleukocytosis management strategies
• Rare conditions:
  • Consideration of referral to specialized centers
  • Enrollment in registries and research protocols when appropriate
  • Interdisciplinary tumor boards for complex cases
  • Telehealth consultation with national experts
• End-of-life considerations:
  • Early palliative care integration for high-risk diagnoses
  • Advance care planning discussions
  • Symptom management protocols
  • Family support resources and bereavement services