Stage IV Wilms tumor with intracardiac extension: a case highlighting challenges in resource-limited settings—a case report

Wilms tumor (nephroblastoma) is the most common renal malignancy and the second most common intra-abdominal cancer in children, typically diagnosed before the age of five. Vascular invasion with tumor thrombus formation occurs in up to 30% of cases, with 4–10% extending into the inferior vena cava; however, intracardiac extension into the right atrium is exceedingly rare, occurring in fewer than 1% of cases. These advanced presentations demand timely, multidisciplinary management, which can be particularly difficult to achieve in resource-limited settings. We report a case of a 3-year-old female Ethiopian patient who presented with progressive abdominal swelling, constitutional symptoms, and respiratory distress. Imaging revealed a large left renal mass with multiple para-aortic lymphadenopathies, a solitary pulmonary metastasis, and a tumor thrombus extending into the right atrium. The patient was diagnosed with Stage IV Wilms tumor based on imaging findings though histopathological confirmation was not obtained. She was initiated on neoadjuvant chemotherapy per the SIOP protocol. After four weeks of treatment with the VAD regimen (vincristine, actinomycin D, and doxorubicin), echocardiography showed complete resolution of the right atrial thrombus, and imaging demonstrated reduction in tumor and metastatic lesion size. However, the tumor thrombus in the proximal inferior vena cava (IVC) persisted. Intensified chemotherapy with a four-drug regimen (carboplatin, etoposide, cyclophosphamide, and doxorubicin) was continued over a total of 34 weeks. Surgical resection was planned but could not be performed due to the unavailability of cardiopulmonary bypass and specialized pediatric oncology surgical expertise. The patient was lost to follow-up for four weeks, during which time the tumor rapidly progressed. Upon return, she developed right-sided hemiparesis; brain CT showed no evidence of intracranial metastasis, hemorrhage, or acute infarct. The patient ultimately died from respiratory failure secondary to massive tumor progression. This case highlights the complexities in managing high-risk Wilms tumor with extensive vascular and metastatic involvement, especially in resource-constrained environments. While chemotherapy may achieve temporary regression of tumor thrombi, timely surgical intervention remains critical for long-term survival. This case underscores the urgent need to improve access to pediatric oncology and surgical care, including cardiopulmonary bypass capabilities, in low-resource settings.