What is in the Differential Diagnosis of an Abdominal Mass?

Patient Presentation
A 3-year-old male came to clinic because his parents noted that his abdomen was hard on the right side when they squeezed his abdomen while they were playing 2 days ago.
The past medical history was normal.
The family history was negative.
The review of systems was negative including weight loss, chills, fever, sweats, bone or other pain, adenopathy, bleeding, bruising or change in bowel or bladder habits. He also had normal satiety and was eating well.
The pertinent physical exam with normal vital signs, growth and development. Abdomen reveals a diffuse solid mass in the right mid- to upper quadrant. No splenomegaly was noted. Shoddy anterior cervical and inguinal nodes were noted. Skin examination was normal.
The work-up showed normal complete blood count, erythrocyte sedimentation rate, lactate dehydrogenase, liver enzymes, and total bilirubin.
The radiologic evaluation revealed a large mass that appeared adherent to the liver that did not appear to be arising from the kidney or the adrenal grand. The patient then had an alpha-fetoprotein level drawn that was significantly elevated and a surgical biopsy confirmed a
diagnosis of hepatoblastoma. The child is undergoing chemotherapy to shrink the tumor and surgical resection is planned for the future.

Figure 33 – Axial image from a CT scan of the abdomen performed with intravenous and oral contrast. A large, inhomogenous mass is seen on the right side of the abdomen, compressing the right kidney posteriorly. The mass did not appear to arise from the right adrenal gland or right kidney.

Approximately 70% of liver tumors are malignant with hepatoblastoma predominating in those < 3 years and hepatocellular carcinoma becoming more common in older children.
Hepatoendothelioma is the most common benign tumor. Liver tumors usually present as a painless abdominal mass but they can also cause weight loss, anorexia, fever or jaundice.
Alpha-fetoprotein levels are elevated in hepatoblastoma and hepatocellular carcinoma. Hepatoblastoma is more common in children with Beckwith-Wiedemann syndrome and hemihypertrophy.
Resection is the mainstay of treatment but chemotherapy to shrink a large tumor or after resection is also used. Favorable factors for prognosis are decreasing alpha-fetoprotein levels and complete resections.
Overall disease free survival is 70% except for those patients presenting with initial metastatic disease.

Learning Point
The differential diagnosis of an abdominal mass depends on the location, age of the patient, and imaging results but includes:

  • Abdominal organs that are normal but are mistaken as a mass – e.g. liver, spleen, kidney, aorta, bladder, uterus, etc.
  • Organ enlargement – e.g. storage disease, congestive heart failure, infection, etc.
  • Gastrointestinal anatomic abnormality – e.g. bowel duplication, stenosis, appendiceal abscess, etc.
  • Renal abnormalitiy – e.g. hydronephrosis, megaureter, polycystic kidney disease, renal vein thrombosis, etc.
  • Tumors – primary or metastatic, but most commonly neuroblastoma, Wilm’s tumor, and lymphoma. Other malignancies include hepatocellular carcinoma, hepatoblastoma, rhabdomyosarcoma,
    ovarian or testicular germ cell tumors, and primary neuroectodermal tumors. Benign tumors may also occur such as teratomas.

  • Cysts – e.g. choledochal cyst, mesenteric cyst, pancreatic pseudocyst, omental cyst, ovarian cyst, meconium pseudocyst, urachal cyst, etc.
  • Miscellaneous – e.g. abscess, fecal mass, hydrops of gall bladder, intussusception, pregnancy, pyloric stenosis, hydrometrocolpos, adrenal hemorrhaage, etc.

Questions for Further Discussion
1. What should be included in the workup of an abdominal mass? Why?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Information prescriptions for patients can be found at MEDLINEplus for this topic: Liver Cancer

To view current news articles on this topic check Google News.

Sheldon SH Levy HB. Pediatric Differential Diagnosis. Second Edition. Raven Press: New York. 1985:1-4.

Woodhead JC. Pediatric Clerkship Guide. Mosby. St. Louis MO, 2003:115-120.

Rudolph CD, et.al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1375-1376, 1620-21.

ACGME Competencies Highlighted by Case

  • Patient Care
    2. Essential and accurate information about the patients is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    7. All medical and invasive procedures considered essential for the area of practice are competency performed.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

    Donna M. D’Alessandro, MD
    Associate Professor of Pediatrics, Children’s Hospital of Iowa

    January 30, 2006