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P11) Palpable abdominal mass and microscopic hematuria in a child
Review the Learning Outcomes, Hx, PE and Labs, and begin the module with your Provisional Diagnosis. Keep hitting "Next" to move through the module.
Learning Outcomes
- Articulate your relationship with the consulting diagnostic radiologists in the evaluation of a pediatric patient with a palpable abdominal mass.
- Review the DDx considerations in a pediatric patient with a palpable abdominal mass.
- Identify the spectrum of imaging findings in appropriate modalities for evaluating a pediatric patient with a palpable abdominal mass.
History
A 4-year-old boy was brought to his primary care provider after his mother discovered an abdominal mass during bath time. An ultrasound was performed, which revealed a large, well-defined, heterogeneous mass in the abdomen. He was referred to the hospital for further evaluation and workup. The boy has not experienced any abdominal pain and remains otherwise asymptomatic, with age-appropriate developmental milestones.
Physical Exam
BP: 134/82, HR 90, RR 18, Temp 37C, O2 saturation 99%.
General: Well-developed child in no apparent distress.
Abdomen: Large, smooth, non-tender mass on the left side.
Labs
Urinalysis with microscopy:
Color: Yellow, Blood: Positive, RBCs: 6/hpf, Protein: Negative
Provisional Diagnosis
Select the Dx you believe is most appropriate
This patient most likely has a renal mass, given the presentation (palpable abdominal mass, age, hypertension) and laboratory findings (microscopic hematuria).
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Potential Acuity
What is your assessment of the likely acuity for this patient?
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The patient requires routine, but expedited workup for their condition.
First Imaging Study
What is the first imaging study you will order?
An abdominal ultrasound is the preferred initial imaging study for evaluating a palpable abdominal mass in the pediatric population. As an ultrasound has already been performed in this case, a CT scan should be ordered to provide further characterization and staging of the mass.
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Pertinent Imaging Observations
Click on the links below to view images from the study, and assess these key findings as best you can.
CT Case
The left sided renal mass originates:
As the mass distorts the kidney and produces the “claw sign”, it arises from within the renal parenchyma.
The left sided renal mass is:
The mass is retroperitoneal, as it involves the kidney.
The hypodense region in the mass likely represents:
Given that the mean Hounsfield Units are -60.25, this likely indicates the presence of fat, which typically has a value between -30 and -100 HU. Water has a Hounsfield Unit value of 0 HU, while blood has a Hounsfield Unit value ranging from 30 to 70 HU.
The mass is:
This mass exhibits heterogeneity. Given the presence of a fat-density region, it is consistent with the characteristics of a Wilms tumor.
View the full study if you'd like to take a look yourself.
Second Imaging Study
What is the next imaging study you will order?
Since the presence of a renal tumor has already been established, additional abdominal imaging may not be necessary. However, an ultrasound could be beneficial in further evaluating the renal vasculature, which was not adequately visualized on the CT scan. An X-ray or CT of the chest should be performed to assess for the presence of lung metastases.
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What is your Diagnosis now that you have seen the imaging results?
The imaging features are consistent with a Wilms tumor; however, other renal tumors such as clear cell carcinoma or rhabdoid tumors should also be considered as part of the differential diagnosis.
Current Acuity
Initially, you selected and we suggested acuity.
Has your concern for this patient changed?
Routine. The patient requires routine, but expedited workup.
Assessment and Plan
Please provide your assessment and plan for this patient
The patient is a 4-year-old male with a Wilms tumor detected on imaging. A chest X-ray or chest CT should be performed to evaluate for lung metastases. We will refer the patient to pediatric surgery for evaluation of nephrectomy and to pediatric oncology for further management.
Lessons Learned:
- Wilms tumor is the most common renal malignancy in children and typically presents between the ages of 2 and 4 with an abdominal mass or swelling.
- Other symptoms may include abdominal pain, hematuria, or hypertension.
- Lungs are the most common site of metastases for Wilms tumors, and chest imaging is routinely performed following diagnosis.
- Wilms tumor is associated with multiple congenital syndromes, including WAGR syndrome, Beckwith-Wiedemann syndrome, and Denys-Drash syndrome.
- An abdominal ultrasound is the best initial imaging study to identify and differentiate Wilms tumor from other abdominal masses, followed by CT or MRI to evaluate the nature and extent of the mass.
- In CT imaging, the typical finding for Wilms tumor is a heterogeneous mass with areas of fat or calcification that arise from the renal parenchyma, resulting in displacement of the kidney and the "claw sign."
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