Invasive leiomyosarcoma involving the tongue of an Arabian mare.
Authors: Pinzón-Osorio César Augusto, Meneses-Martínez Henry, Botero-Espinosa Lucía, Herrera-Luna Carlos Vladimir
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Leiomyosarcoma of the Equine Tongue A 10-year-old endurance Arabian mare presented with a four-month clinical history of profuse salivation, difficulty swallowing, severe halitosis and abnormal chewing, findings that prompted comprehensive diagnostic investigation including physical examination, haematology, biochemistry, computed tomography and histopathological analysis. CT imaging revealed a homogeneous mass invading the ventral aspect of the tongue, measuring approximately 10 × 15 × 8 cm at necropsy, alongside secondary changes including mineralisation at the left mandibular border and lymph node enlargement. Histological examination combined with immunohistochemical staining (positive for Calponin and Desmin) confirmed the diagnosis of leiomyosarcoma—a malignant soft tissue tumour of smooth muscle origin, likely arising from perivascular tissues within the tongue. This case represents the first equine oral leiomyosarcoma to be fully characterised using integrated histopathology, immunohistochemistry and advanced imaging, establishing a diagnostic precedent for this exceptionally rare neoplasia. Whilst the prognosis for such invasive oral masses remains poor, awareness of this differential diagnosis alongside the classical signs of progressive dysphagia, ptyalism and halitosis will enable equine practitioners to pursue appropriate diagnostic pathways and provide informed prognostic counselling to owners of affected horses.
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Practical Takeaways
- •Leiomyosarcomas are extremely rare oral tumors in horses; persistent ptyalism, dysphagia, and halitosis warrant investigation including CT imaging and biopsy for definitive diagnosis
- •Combined histopathology and immunohistochemistry (Calponin/Desmin staining) is essential for confirming leiomyosarcoma diagnosis and distinguishing it from other mesenchymal tumors
- •Oral masses in horses causing dysphagia and dysmastication require imaging to assess extent of invasion and involvement of surrounding structures before treatment planning
Key Findings
- •A 10-year-old Arabian mare presented with a 10 × 15 × 8 cm invasive leiomyosarcoma of the tongue with four-month history of ptyalism, dysphagia, and halitosis
- •CT imaging confirmed the mass location and degree of invasion on the tongue, along with submandibular lymph node enlargement
- •Immunohistochemistry positive for Calponin and Desmin confirmed soft tissue leiomyosarcoma originating from perivascular wall tissue
- •This is the first reported case of oral leiomyosarcoma in a horse utilizing histopathology, immunohistochemistry, and imaging for diagnosis