Chest / Cardiac for Monday, June 1st, 2026

Contributed by Vanderbilt Children's Hospital
Corina Do, Sarah Dulaney, and Melissa Hilmes.

History

This is a 3-year-old boy born prematurely at 33 weeks who presented to the Emergency Department with 3 weeks of progressively worsening fatigue, cough, wheezing, and labored breathing. Chest radiographs was performed.

Images (Click any image to enlarge)

Chest radiograph AP view
Chest radiograph lateral view

Question

What is the most likely diagnosis?

Your answer

Please log in to see your results.

Correct answer

Tumor

Discussion

The patient’s chest CT demonstrated a large pericardial mass that was biopsied, with final pathology showing embryonal rhabdomyosarcoma. He received chemotherapy and had the mass resected a few months later.

Rhabdomyosarcoma is a type of soft tissue malignant tumor arising from mesenchymal cells. The most common subtype is embryonal (70-75% of childhood rhabdomyosarcomas), which has a better prognosis than other subtypes. These tumors may be located in the head, neck, genitourinary tract, or extremities.1

Embryonal rhabdomyosarcoma is the most common soft tissue sarcoma in children and may be associated with familial syndromes such as Noonan, DICER, Neurofibromatosis type I, and Beckwith-Wiedemann. Other risk factors include prematurity, parental drug use, and radiation exposure. The peak incidence is between 0 and 4 years old, and patients between 1 and 9 years old have the best prognosis, with a 5-year survival rate of 87%. Prognosis is also dependent on primary tumor size, site, and pathology.2

Differential diagnosis

  • Pneumonia (bacterial, viral, or complicated with effusion)

  • Pericardial effusion

  • Congenital heart disease

  • Soft tissue malignancy

  • Lymphoma

  • Teratoma

  • Thymoma

  • Asthma

Additional images

Chest CT axial view
Chest CT axial view
Chest CT axial view
Chest CT coronal view
Chest CT sagittal view

References

  • 1. Ognjanovic S, Linabery AM, Charbonneau B, Ross JA. Trends in childhood rhabdomyosarcoma incidence and survival in the United States, 1975-2005. Cancer. 2009;115(18):4218-4226. doi:10.1002/cncr.24465
  • 2. PDQ Pediatric Treatment Editorial Board. Childhood Rhabdomyosarcoma Treatment (PDQ®)–Health Professional Version. National Cancer Institute. Updated April 11, 2025. Accessed March 8, 2026. https://www.cancer.gov/types/soft-tissue-sarcoma/hp/rhabdomyosarcoma-treatment-pdq