Pleuropulmonary blastoma in an equine fetus.
Authors: Woolford L, Staniek G, Blunden A S
Journal: Veterinary pathology
Summary
Pleuropulmonary blastoma (PPB) is a rare embryonic tumour well-documented in human paediatrics but never previously reported in equine medicine; this case describes the first recognised occurrence in an equine fetus, identified as a soft, multicystic mass in the right caudal lung lobe during routine pathological examination. Histological analysis revealed a biphasic neoplasm comprising primitive mesenchymal tissue interspersed with well-differentiated cuboidal epithelial ducts and cystic structures, with immunohistochemical staining confirming vimentin positivity in mesenchymal cells and strong cytokeratin expression in the epithelial components. The morphological features—pleural location, dual solid–cystic architecture, and prenatal presentation—were consistent with human PPB classifications, establishing this as a truly analogous condition rather than a superficially similar lesion. Whilst the clinical significance for equine practitioners remains limited given the rarity of the condition and lack of live cases documented, recognition of PPB in differential diagnoses during prenatal or neonatal pulmonary pathology may be warranted, particularly when embryonic tumours are suspected. Further case documentation and investigation into potential underlying genetic predisposition factors would strengthen understanding of whether this represents a genuine disease entity in equine species or an incidental developmental anomaly.
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Practical Takeaways
- •This case demonstrates that pleuropulmonary blastoma, previously only documented in humans, can occur in equine fetuses and should be considered in differential diagnoses of fetal lung masses
- •Awareness of this rare neoplasm may be relevant for veterinarians performing prenatal imaging or conducting fetal necropsies
Key Findings
- •First reported case of pleuropulmonary blastoma in an equine fetus with histopathological and immunohistochemical characteristics similar to human PPB
- •Tumor was a pleural-based multicystic mass in the right caudal lung lobe comprising mesenchymal and epithelial components
- •Mesenchymal elements showed vimentin immunoreactivity while epithelial cells lining ducts showed strong cytokeratin immunoreactivity