Abdominal Mass in a 4-Month-Old Infant (Case 50)

Chapter 69 Abdominal Mass in a 4-Month-Old Infant (Case 50)



Douglas Katz, MD



Differential Diagnosis











Wilms’ tumor Hepatoblastoma
Neuroblastoma Hirschsprung’s disease



Speaking Intelligently


Many children are identified as having an abdominal mass, and often their families and referring physicians are worried that it may be malignant. My primary goal in the evaluation is to determine whether or not the mass is malignant and then identify the appropriate surgical tx. A complete hx and physical examination is performed at the outset. In addition to providing important clues as to the exact dx, a thorough initial evaluation demonstrates to the family that I am taking this problem very seriously and helps alleviate parental anxiety.



PATIENT CARE



Clinical Thinking



• The majority of children diagnosed with an “abdominal mass” do not need surgical intervention. A significant number of children will have constipation or a distended bladder confused with a more serious problem.

• Favorable outcomes and the avoidance of complications often depend on a timely, accurate dx.


History



• When the mass was first noted and any changes in the size are important information.

• Patients with neuroblastoma often have bone marrow involvement. Anemia will cause them to have less energy and more fatigue.

• Time of first passage of meconium and the subsequent stool pattern are essential information when evaluating for Hirschsprung’s disease.

• Hematuria, occult or frank, often with no hx of trauma, may be the presenting sign of a renal tumor.

• A family hx of Hirschsprung’s disease is very important.

• Regression in motor function milestones could indicate invasion of neuroblastoma into the spinal canal.


Physical Examination



• Location, size, and mobility of the mass should be noted.

• Significant hypertension and tachycardia may suggest a vasoactive tumor.

• Neuroblastoma is associated with a number of unique physical findings. Metastatic disease to the skin will appear as small blue nodules. Neuroblastoma can also metastasize to the orbits and create dark circles around the eyes in a pattern that has been described as “panda” eyes. Neuroblastoma can cause opsomyoclonus, which is characterized by myoclonic jerking and a pattern of nystagmus that is called “dancing-eye syndrome.”


Tests for Consideration


















• α-Fetoprotein: Very sensitive for hepatoblastoma (70%–90%).
 $100

• U/A: Hematuria suggestive of Wilms’ tumor.
 $18

• CBC: Anemia is more common with neuroblastoma than with the other tumors.
 $38

• Urine catecholamines: Elevations may suggest a dx of neuroblastoma.
 $50



IMAGING CONSIDERATIONS





















→ Abdominal x-ray (AP supine view): Look for constipation or abdominal mass (e.g., microcalcificatons of a neuroblastoma).
 $156

→ Contrast enema: Barium or water-soluble contrast shows clonic anatomy. Look for narrowed transition of Hirschsprung’s disease.
 $250

→ Ultrasonography: Fast, easily obtained in infants. Should define mass and site of origin; cystic or solid and vascularity.
 $225

→ CT: Rarely used in infants.
 $800

→ MRI: No radiation. Occasionally used for operative planning to evaluate extent of tumor, vascular invasion, and staging.
 $900





















Clinical Entities Medical Knowledge
Wilms’ Tumor
PΦ Wilms’ tumor or nephroblastoma is a diverse group of malignant neoplasms of renal cell origin (nephroblasts). There is marked compression of the normal kidney and may be obstruction of the collecting system.
TP Most often diagnosed as an asymptomatic abdominal mass in children usually less than 15 years of age. May also present with microscopic or gross (occasionally with minimal trauma) hematuria. Tumor occlusion of the left spermatic vein may produce a left varicocele. Often, the parents note abdominal asymmetry while bathing the child.
Dx There are no specific blood or urine tests for Wilms’ tumor. CT is the main imaging study, though MRI is also very sensitive. Ultrasonography and MRI are useful in detecting vascular involvement.
Tx Surgical excision and staging are the main elements of therapy. Biopsy of nonresectable lesions, followed by chemotherapy and often radiation therapy, is eventually followed with surgical resection of remaining tumor. Additional chemotherapy and radiation therapies depend on the stage of tumor. Partial nephrectomy is usually only performed in cases of bilateral disease. See Sabiston 71, Becker 58.


Neuroblastoma















PΦ A tumor of neural crest origin with a widely variable course, ranging from benign maturation and spontaneous regression to widespread metastatic disease. Its cause is unknown. May occur anywhere along the course of the sympathetic chain, most often arising in the adrenal medulla.
TP The majority of patients are diagnosed by 10 years of age. Often presents as a painful, hard, immobile abdominal mass. Weight loss and fever are common, with 25% having hypertension. Other symptoms are dependent on the location of metastases (common), and the production of vasoactive substances.
Dx 24-hour urine specimens have marked elevation in catecholamines and metabolites in most patients. Plain abdominal x-rays will demonstrate stippled calcifications in half of patients. CT and MRI are the imaging studies of choice, and will aid in the dx of metastases. Biopsies are essential, and samples must be of adequate size to allow for multiple biologic and genetic studies.
Tx Tumor excision for low-risk tumors is often curative and is still an important component in the tx of the majority of other cases. Intense chemotherapy is used for most patients, with radiation therapy and bone marrow for the most severe of cases. See Sabiston 71, Becker 58.


Hepatoblastoma















PΦ Arises from a precursor of the mature hepatocyte, usually with expression of different cell types. The cause is not known, but it is often seen in association with genetic syndromes. Usually presents as an expanding solitary mass. Spontaneous focal necrosis is common, and spread via hepatic veins, most often to the lung, is not uncommon.
TP Most often seen as an asymptomatic abdominal mass in infants or very young children. Abdominal pain, weight loss, nausea, and vomiting may be seen in advanced disease.
Dx Marked elevation in α-fetoprotein is seen in nearly 90% of patients. CT and MRI most accurately define the tumor and help determine resectability. Scans of the chest and brain determine metastatic disease.
Tx Initial resection is possible in only 50% of patients. Biopsy is followed by chemotherapy, which is usually very successful in shrinking the tumor. Definitive resection involves a lobectomy or trisegmentectomy. Liver transplantation is used for unresectable tumors with no metastatic disease. See Sabiston 71, Becker 58.


Hirschsprung’s Disease















PΦ Absence of ganglion cells in the distal bowel leads to an inability of the bowel to relax and allow passage of stool. While the exact cause is not known, it is occasionally associated with other genetic conditions.
TP While the dx may occur at any age, most children with constipation since birth, or who failed to pass meconium within the first 2 days of life, should be suspected of having Hirschsprung’s disease. Most cases are now diagnosed within the first 6 months of life. Children can present with constipation, failure to thrive, abdominal distention, and enterocolitis.
Dx Prone cross-table lateral abdominal x-rays may demonstrate absence of distal colonic and rectal air. A contrast enema may demonstrate a transition zone, which is seen less commonly in newborns. Rectal biopsy is the gold standard and may be done at the bedside in infants. It reveals the absence of ganglion cells and the presence of hypertrophied nerve trunks.
Tx The normally innervated bowel is brought closer to the anus using a variety of different surgical techniques. Recently, these procedures have been performed using minimal access techniques or transanally. In some cases, the correction can be done in a single procedure, although in some cases it is preceded by the creation of a colostomy or ileostomy done in the normal bowel. See Sabiston 71, Becker 57.



ZEBRA ZONE



a. Hydronephrosis and multicystic kidney: Hydronephrosis may result from obstruction of the ureter-pelvic junction, ureter-vesicular junction, or a bladder outlet obstruction and can be bilateral. Sonography shows a dilated renal pelvis surrounded by and connected to dilated cystic calyces.

Related posts:

  1. Pigmented Skin Lesion in a 58-Year-Old Female (Case 12)
  2. Professor’s Pearls: Pediatric Surgery
  3. Splenomegaly in a 40-Year-Old Female (Case 19)
  4. The Resident as Teacher: Facilitating Student Success

Stay updated, free articles. Join our Telegram channel
Tags:
Mar 20, 2017 | Posted by in GENERAL SURGERY | Comments Off on Abdominal Mass in a 4-Month-Old Infant (Case 50)

Full access? Get Clinical Tree
Get Clinical Tree app for offline access