Pleuropulmonary blastoma diagnosed after initial rhabdomyosarcoma interpretation in a 2-year-old boyCase report shows rare lung cancer in toddler with DICER1

Frontiers in Medicine Published June 5, 2026 DOI ↗ Editorial oversight: Dr. Sofia Müller, MD · Lifespan & Whole-Person Care

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Key Takeaway

Consider pleuropulmonary blastoma in aggressive pediatric thoracic masses and ensure expert pathology and molecular testing.

This is a case report of a 2-year-old boy with a pediatric thoracic malignancy. The initial CT-guided biopsy was interpreted as embryonal rhabdomyosarcoma, and he received systemic therapy with VAC then VDC, followed by definitive resection and IVADo chemotherapy. The final pathological diagnosis was pleuropulmonary blastoma, type III, and genetic testing detected a pathogenic DICER1 variant. Severe cytopenias were reported as an adverse event during treatment.

The authors note that pleuropulmonary blastoma should be prioritized in the differential diagnosis of aggressive pediatric intrathoracic masses with pneumothorax and mass effect. They emphasize the value of adequate tissue sampling, expert pathology review, and early integration of molecular testing. No pooled effect sizes or comparative outcomes are reported, as this is a single-patient case.

Limitations include the single-patient design, which precludes generalization, and the absence of a comparator group or follow-up duration. The practice relevance is that clinicians should consider pleuropulmonary blastoma in similar presentations and ensure comprehensive diagnostic evaluation.

This case report describes a boy aged 2 years 11 months with a thoracic mass initially thought to be embryonal rhabdomyosarcoma. After initial therapy and surgery, the final diagnosis was pleuropulmonary blastoma, type III, and genetic testing found a pathogenic DICER1 variant.

The child received several chemotherapy drugs, including vincristine, actinomycin, cyclophosphamide, doxorubicin, and dacarbazine, and experienced severe cytopenias as a side effect. The report notes that adequate tissue sampling, expert pathology review, and early molecular testing were valuable in reaching the correct diagnosis.

Because this is a single case, the findings are not generalizable. It shows how a diagnosis can change with more information, but it does not prove a specific treatment works for everyone.

Readers should understand that pleuropulmonary blastoma should be considered in children with aggressive thoracic masses, and that genetic testing can guide care, but this report alone does not change standard practice.

What this means for you:

A toddler’s lung tumor was reclassified as a rare DICER1-linked cancer, changing his treatment plan.

Study Details

Study typeSystematic review

EvidenceLevel 1

PublishedMay 2026

View Original Abstract ↓

BackgroundPleuropulmonary blastoma (PPB) is a rare, aggressive pediatric thoracic malignancy and a sentinel tumor for DICER1 syndrome. Advanced PPB can mimic other pediatric sarcomas and complex cystic lung lesions, creating diagnostic and management pitfalls.Case presentationA boy aged 2 years 11 months presented with progressive respiratory distress and fever due to a rapidly enlarging right hemithorax mass with marked mediastinal shift, near-complete right lung collapse, and recurrent pneumothorax. Initial CT-guided biopsy was interpreted as embryonal rhabdomyosarcoma (ERMS) on limited material, and systemic therapy was started with VAC, later escalated to VDC because of poor response and ongoing life-threatening mass effect. The clinical course was complicated by persistent/recurrent pneumothorax requiring multiple pleural interventions and eventual transfer for urgent surgical management. He underwent near-total resection followed by repeat resection for rapid local recurrence several weeks later. Definitive resection pathology established PPB, type III, and tumor next-generation sequencing detected a pathogenic DICER1 variant (germline status not yet confirmed). Postoperatively, chemotherapy was initiated with IVADo. A complete blood count obtained locally after return home showed severe cytopenias, prompting growth-factor support and close hematology-oncology follow-up.ConclusionThis case highlights that PPB should be prioritized in the differential diagnosis of aggressive pediatric intrathoracic masses with pneumothorax and mass effect, and demonstrates the value of adequate tissue sampling, expert pathology review, and early integration of molecular testing to prevent protocol misdirection and to trigger DICER1-directed genetic counseling and surveillance.

Pleuropulmonary blastoma diagnosed after initial rhabdomyosarcoma interpretation in a 2-year-old boyCase report shows rare lung cancer in toddler with DICER1

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Pleuropulmonary blastoma diagnosed after initial rhabdomyosarcoma interpretation in a 2-year-old boyCase report shows rare lung cancer in toddler with DICER1

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