Virtual Pediatric Patients

Case 2 - A Child With An Abdominal Mass

Donna M. D'Alessandro M.D., Tamra E. Takle M2
Peer Review Status: Internally Peer Reviewed

The Problem / Clinical Presentation
"Brent has been a really healthy boy without any medical problems. He's always been a bit thin but he reached his developmental milestones a little sooner than his two brothers. I took him to his regular pediatrician for a routine 3-year old check-up on a Friday afternoon. I couldn't believe it when she told me he had a lump in his belly and he'd have to get a CAT scan. So we went to our local hospital and had the test. They promised that they would call us as soon as they had the results. After dinner, they called to say a nurse would come to the house to discuss what they had found. That's when I knew something was very wrong. The nurse said the lump may be cancer and we'd have to go to the University of Iowa to have it looked at early the next morning. It was a very long and sleepless night for me and my husband."

"In a short period of time, our life turned around completely."

Clinical Physical Exam
Just as Brent's pediatrician had found, the clinical team at the University of Iowa palpated a mass in the left upper quadrant of the abdomen. The mass was firm, non-tender, non-mobile and extended toward the midline. He had no hepatosplenomegaly or lymphadenopathy. There were no obvious skin lesions or bony abnormalities.

Clinical Differential Diagnosis
The differential diagnosis for a 3 year old with an unrecognized left upper quadrant mass that crosses the midline would include:

• Neuroblastoma
• Other tumors such as lymphoma, rhabdomyosarcoma or Wilms Tumor
• Splenomegaly - cause undetermined at this time
• Anatomic renal abnormalities such as hydronephrosis.

Clinical Labs
A CBC and differential showed a slight lymphocytosis and thrombocytosis. Electrolytes and urinalysis were normal, but liver enzymes were slightly elevated. Other clinical labs obtained included a 24-hour urine for catecholamines (epinephrine, norepinephrine, dopamine, Vanilmandelic acid, Homovanillic acid) which were elevated. A serum ferratin was normal and was obtained for potential staging and prognosis.

Laboratory Differential Diagnosis
Solid malignancy with Neuroblastoma as most likely cause.

Imaging Findings
A CT scan of the abdomen was obtained with IV and oral contrast. It showed a large calcified mass originating from the left adrenal gland. The mass was 12 cm long, 9 cm wide and 7 cm high. The mass crossed the midline displacing the spleen laterally and the left kidney inferolaterally. The mass encased the celiac axis and superior mesenteric artery. A bone scan, bone survey, and chest CT were performed to check for possible metastases. They showed no evidence of metastatic disease.

Imaging Differential Diagnosis
Because the mass appeared adrenal in origin, displaced inferolaterally an otherwise normal-looking left kidney, crossed the midline, and was calcified, it was felt to be a classic appearance for a neuroblastoma. Classic appearance for a Wilms Tumor is a mass that is renal in origin, distorts the architecture of the kidney, remains on one side of the abdomen and is non-calcified.

Operative Intervention
An open surgical biopsy was performed by a pediatric surgeon through an abdominal incision to obtain enough tissue to allow for the correct pathologic diagnosis. A bone marrow biopsy was performed to rule out metastatic disease and was negative for evidence of tumor.

Pathological Findings
The gross specimen was described as a rubbery fragment of soft tissue containing a central white firm area with irregular borders. Histological specimens show portions of tumor in which there are small, regular, round blue tumor cells that are slightly larger than lymphocytes, as well as more enlarged tumor cells, some of which are multinucleated. Diffuse throughout the tumor are ganglion cells in various stages of maturation. The cells are arranged in a pseudoalveolar pattern with fibrous septae, hemorrhage, focal calcification, and small areas of necrosis. However, rosettes are not appreciated.

Pathological Diagnosis
Differentiating Neuroblastoma

Treatment Course, Prognosis and Follow-up
Because Brent's tumor encased most of the major vessels in the abdomen, it was initially considered unresectable. Therefore the therapeutic plan for him is to shrink the tumor's size through chemotherapy so it can eventually be surgically removed.

After the initial diagnosis and commencement of therapy, Brent's mother again remarked how, "In a short period of time, our life turned around completely. A month ago, we saw Brent as a normal, healthy child. Now he has to deal with a serious illness. He asks me regularly if he is still sick, and when I answer yes, he insists that he doesn't feel sick."

"I'm trying not to let this disrupt Brent's older brother's life any more than necessary. Garrett is playing T-ball and taking swimming lessons during the summer. Garrett has exhibited curiosity and interest in Brent's disease. I have explained to Garrett that Brent has a 'hard thing' in his tummy that will take a long time to come out, that it will take some strong medicine to make him better, and that he has to be in the hospital when they give him this strong medicine."

"Brent has always been wary around strangers. It was no surprise to me that he was cool to the doctors, initially. After the first week, he was been warming up to them. However, Brent resisted taking oral medicines since he's never had to take oral medicines before, aside from an occasional Tylenol. He's resisting the loss of control in his life, and I try to give him choices with his medicines such as whether to take the yellow or the blue first in order to help him regain some sense of control."

"They told me he'd have to have some chemotherapy and it may make his hair fall out. He has had a full head of hair since he was a baby, and I wanted a portrait of him before he started his treatment. He surprised me by saying he didn't want his picture taken and agreed only after I promised it would not be another picture of his tummy."

"In the fall, I am planning to teach only part-time. I had planned to do this anyway to have more time for myself, but now the time will be for Brent. We are a normal family dealing with extraordinary circumstances, and it is a real challenge to try to stay normal."

The Approach to the Child With an Abdominal Mass

Differential Diagnosis

The differential diagnosis for a child with an abdominal mass can include:

• Normal intra-abdominal organs - especially liver, spleen, bladder, and aorta
• Feces
• Ascites
• Pyloric stenosis
• Intussusception
• Inflammatory bowel disease
• Bowel duplication
• Hydronephrosis
• Megaureter
• Polycystic kidneys
• Pancreatic pseudocyst
• Hydrops of the gallbladder
• Wilms tumor
• Neuroblastoma
• Lymphoma
• Rhabdomyosarcoma
• Anterior meningomyelocele
• Urachal Cyst
• Ovarian cysts and tumors
• Teratomas
• Pregnancy

History and Physical

A complete history should be taken from the patient and/or family. Because of the differential diagnosis above, attention should be given to the length of time since the mass was noticed, any associated pain, changes in eating and elimination patterns, night sweats, fatigue, malaise, bleeding or bruising, skin changes, and sexual history.

The physical examination should attend to the location, configuration, size, consistency, mobility and tenderness of the mass. Other systemic signs to look for include hepatosplenomegaly, lymphadenopathy, skin changes, and hemodynamic changes.

Evaluation

Imaging of the abdomen is the first step in the evaluation process. Its results will guide the rest of the evaluation. Imaging should begin with an abdominal radiograph. Ultrasound is most commonly done next. If necessary, intravenous pyelography (IVP), computed tomography or magnetic resonance imaging can add more information.

The differential diagnosis and imaging results for the individual patient also guide the laboratory evaluation. Considerations for the initial laboratory evaluation can include:

Blood

CBC, differential and platelets - for anemia, consumptive or malignant processes
BUN/Creatinine - for renal function
Electrolytes - for electrolyte disturbances
Liver Function Tests - for infiltrative or inflammatory processes
Amylase/Lipase - for inflammatory process
Calcium, Magnesium, Phosphorous - for malignant processes or electrolyte disturbances

Urine

Urinalysis - for renal process
Vanilmandelic Acid/Homovanillic Acid - for possible neuroblastoma

Stool

Guaiac - for blood in stool with inflammatory or infectious process

Consultation

Surgery - for possible surgical management
Oncology - for possible oncological management

Other

Steroid Hormones - for possible ovarian tumors
Beta hCG - for pregnancy

Neuroblastoma Discussion

Clinical Presentation
Neuroblastoma is one of the most common solid tumors seen in childhood. The incidence peaks in the first 5 years of life (85%) with 50% of patients less than 2 years old. The most common tumor site is the abdomen (60%) and 70% of these are adrenal. Of the other locations, 13% are in the thorax, 5% are in the neck, 4% are in the pelvis, and 2% are in the posterior fossa and olfactory bulb. There does not appear to be familial occurrence. Neuroblastoma is more common in males but can be seen in either sex. Ninety-five percent of neuroblastomas produce excess catecholamines which cause paroxysmal episodes of profuse sweating and flushing, headache, tachycardia, hypertension, diarrhea refractory to conventional therapy, and acute cerebellar encephalopathy (opsoclonus-myoclonus, ataxia). Seventy-five percent of patients present with symptoms related to metastases.

Pathophysiology
Neuroblastoma arises from neural crest cells along the sympathetic chain, and commonly presents as a malignancy of the adrenal gland. Neuroblastomas represent a spectrum of differentiation of primitive neuroblasts into mature ganglion cells. Poorly differentiated tumors have a poor prognosis. Spread is via direct invasion, blood, and lymphatics. Seventy percent have early marrow involvement and skeletal and hepatic metastases are also common.

Lab Findings
The laboratory testing along with age and stage helps in determining prognosis and currently includes the following:

• Ferritin
• Neuron-specific enolase
• Chromogranin
• GD2 Ganglioside
• Urine VMA/HVA
• gp140TRK-A
• N-Myc Amplification
• DNA Index
• 1p Deletion

Imaging Findings
Sixty-six percent of neuroblastomas are calcified on an abdominal radiograph. Ultrasound shows a solid mass of mixed echogenicity that displaces the kidney, but does not distort it. Computed tomography may better demonstrate the extent of the mass, which is usually heterogeneous in appearance, and may detect liver metastases. Magnetic resonance imaging is especially useful in determining if there is spread of tumor into the spinal canal. A bone scan should be performed to look for bone metastases.

Pathology
Neuroblastomas are one of the small, round, blue cell tumors. The tumors are divided into favorable or unfavorable histology which influences prognosis. The tumors consist of small primitive cells slightly larger than lymphocytes, organized in sheets, with dark nuclei and not much cytoplasm. The cells are often clumped in an alveolar pattern separated by fibrous septae. Some differentiated ganglion cells may be seen. A characteristic feature of neuroblastomas is the Homer-Wright rosette, a cluster of tumor cells around a pale staining fibrillary core.

Differential Diagnosis
The pathological differential includes the small, round, blue cell tumors including:

• Ewing Sarcoma
• Rhabdomyosarcoma
• Burkitt Lymphoma
• Acute Lymphoblastic Lymphoma/Leukemia
• Wilms Tumor
• Retinoblastoma
• Medulloblastoma

Treatment
Factors affecting treatment are the age of the child and extent of the tumor. An International Neuroblastoma Staging System has been developed and uses the following characteristics for classification:

Stage 1	Tumor localized to area of origin
Stage 2	Tumor extends beyond organ of origin, but does not cross the midline
Stage 3	Tumor crosses the midline, ipsilateral lymph nodes may or may not be involved
Stage 4	Metastases of tumor to distant lymph nodes, viscera, bones and soft tissue
Stage 4S (Special)	Localized primary tumor with metastases confined to liver, skin and bone marrow

Combination therapy of the following modalities is generally used and is personalized for an individual child:

• Surgical removal initially or after other modalities
• Chemotherapy
• Radiation therapy
• Bone marrow transplant

Prognosis
Epidemiological data provides information for groups of patients with similar disease characteristics. For neuroblastoma, prognosis is divided into low, intermediate and high risk groups. The long term survival rate for the low and intermediate risk groups is excellent with 95-100% and 80-90% survival respectively. The high risk group has an overall survival rate of 30%.

References
Matthay KK. Neuroblastoma: A Clinical Challenge and Biologic Puzzle. CA: A Cancer Journal for Clinicians 1995: 45, 179-192.

Ravel R. Clinical Laboratory Medicine 6th Ed. St. Louis: Mosby, 1995

Sheldon, Stephen H. and Levy, Howard B. Pediatric Differential Diagnosis. Raven Press. 1985.

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