CT-guided laser treatment resolves rare sinus pneumocoele in filly

A new Equine Veterinary Journal case report details the diagnosis and treatment of pneumocoele sinus in a 2-year-old Cob filly, a rare condition involving abnormal air expansion of the paranasal sinuses with thinning or erosion of surrounding bone. The filly presented with progressive inspiratory stertor, and the authors report that CT imaging was essential to define the lesion and guide treatment. They used transnasal diode-laser fenestrations to establish drainage and communication between the conchal sinuses and the nasal cavity, with complete resolution of clinical signs and no long-term recurrence. (beva.onlinelibrary.wiley.com)

That matters in part because sinus gas expansion remains sparsely documented in horses. A multicenter equine case series published in Equine Veterinary Education identified just eight horses with sinus gas expansion, including seven classified as sinus pneumocoele and one as pneumosinus dilatans. In that series, the condition was described as slowly progressive, inconsistently associated with clinical signs, and still poorly understood pathophysiologically. The distinction between pneumocoele and pneumosinus dilatans generally hinges on whether CT shows bone erosion or thinning beyond normal sinus boundaries, a framework borrowed from human medicine. (beva.onlinelibrary.wiley.com)

The new filly case also fits with what clinicians already know about the diagnostic challenge of equine sinus disease. Equine paranasal sinuses are anatomically complex, and overlapping structures can limit the usefulness of standard radiography. Reviews of equine respiratory imaging and sinonasal disease have noted that CT has become especially valuable for head cases because it can characterize air-filled spaces, bone remodeling, mucosal changes, and compartment involvement in multiple planes. That’s particularly relevant when a horse presents with upper airway noise, facial asymmetry, or other atypical signs that don’t neatly fit routine sinusitis or dental-related disease. (pmc.ncbi.nlm.nih.gov)

On treatment, the report’s use of transnasal diode-laser fenestration is notable because it suggests a less invasive option than more extensive open sinus surgery in selected cases. Endoscopic and laser-assisted approaches are already used in parts of equine sinonasal surgery, including fenestration procedures to improve access or drainage in conchal and sinus disease. In this filly, the goal was to create communication between the conchal sinuses and the nasal cavity, relieving the obstructive effects of the lesion while avoiding a more aggressive external approach. Based on the case summary, that strategy was successful at long-term follow-up. (aaep.org)

Industry and clinical commentary around equine sinus care has increasingly emphasized the role of advanced imaging in exactly these kinds of cases. Equine clinicians interviewed by trade outlets have described CT as the best way to assess sinus involvement in many horses, especially because horses are obligate nasal breathers and pathology in this region can have outsized clinical consequences. At the same time, broader adoption of standing CT in equine practice may make earlier and more precise diagnosis of rare conditions like pneumocoele more feasible, though access still varies by referral setting. (equimanagement.com)

Why it matters: For veterinary professionals, this case is less about the rarity alone and more about decision-making. A young horse with progressive inspiratory stertor could easily prompt workups centered on dynamic upper airway disease, soft tissue obstruction, or more common sinus disorders. This report argues for keeping sinus gas expansion on the differential list when imaging or endoscopy findings don’t fully explain the presentation. It also supports CT not just as a confirmatory test, but as the tool that can define lesion extent, classify the process, and shape a surgical plan. In practices with access to advanced imaging and endoscopic laser equipment, the case may broaden thinking about minimally invasive options for selected sinonasal lesions. (beva.onlinelibrary.wiley.com)

There are still important unknowns. The larger equine series suggests these lesions may progress slowly, and at least one horse had CT-documented progression over 26 months. The underlying mechanism remains unclear, and the literature is too small to say with confidence which cases are best managed conservatively, with fenestration, or with more extensive surgery. For now, this filly’s outcome offers a useful proof of concept: in the right anatomy, CT-guided transnasal diode-laser fenestration may offer durable relief with less surgical morbidity. (beva.onlinelibrary.wiley.com)

What to watch: Watch for the full case report to inform how the authors selected the surgical approach, how follow-up was defined, and whether future series can identify recurrence rates, ideal case selection criteria, and any role for standing CT in earlier diagnosis. (beva.onlinelibrary.wiley.com)