Study maps thoracic CT patterns in canine blastomycosis

A new study in Veterinary Radiology & Ultrasound offers one of the clearest recent descriptions of thoracic CT findings in dogs with blastomycosis, a fungal disease that still creates diagnostic uncertainty in general practice, emergency settings, and referral hospitals. In this single-center retrospective case series, investigators reviewed 23 dogs with blastomycosis and found that multilobar pulmonary nodules, consolidation with ground-glass attenuation, and tracheobronchial lymphadenomegaly were the most common thoracic CT abnormalities. (eurekamag.com)

That matters because blastomycosis can be clinically and radiographically messy. The disease is acquired by inhalation of Blastomyces organisms, with the lungs serving as the primary site of infection in most dogs, and it may later disseminate to the skin, eyes, lymph nodes, bone, testes, or central nervous system. Merck Veterinary Manual notes that thoracic imaging in affected dogs often shows noncalcified nodules or consolidation plus bronchial or mediastinal lymph node enlargement, but those findings overlap with neoplasia and other infectious or inflammatory disease. (merckvetmanual.com)

The new paper helps refine that picture for CT users. According to the study summary, board-certified radiologists reviewed thoracic CT studies from dogs with confirmed or presumed pulmonary involvement. The most frequent pattern was not a solitary lesion but multilobar disease, with nodules and consolidation often accompanied by ground-glass opacity and tracheobronchial lymphadenomegaly. That supports the idea that when blastomycosis is present in the chest, CT may reveal a broader and more distributed pulmonary process than plain radiographs initially suggest. (eurekamag.com)

The broader literature helps put the findings in context. A prior human CT series concluded there was no single CT abnormality diagnostic for blastomycosis, underscoring how nonspecific fungal pulmonary inflammation can be on advanced imaging. In dogs, older diagnostic studies have shown that pulmonary blastomycosis is often worked up through cytology, antigen testing, and thoracic imaging together, rather than imaging alone. A large retrospective study of 125 canine pulmonary blastomycosis cases also highlighted the practical role of diagnostic testing and medical treatment decisions once suspicion is raised. (pmc.ncbi.nlm.nih.gov)

Direct outside commentary on this specific paper appears limited so far, which isn't unusual for a specialty imaging study. Still, existing expert resources align with its main message. Merck’s veterinary reference describes pulmonary nodules, consolidation, and thoracic lymphadenopathy as expected thoracic manifestations, while educational imaging materials from veterinary radiology groups emphasize that blastomycosis can produce variable thoracic and extra-thoracic imaging findings. Taken together, the new study appears less like a challenge to current understanding and more like a useful refinement of it for CT-era practice. (merckvetmanual.com)

Why it matters: For veterinarians, especially in endemic regions around river valleys, the Great Lakes, and other recognized risk areas, this study may improve how quickly blastomycosis enters the differential when CT shows multifocal nodular and consolidative lung disease with regional lymphadenopathy. That could be especially useful in referral cases where pet parents have already moved beyond radiographs and where the working list may still include metastatic disease, granulomatous pneumonia, or other systemic mycoses. Faster recognition won't replace organism identification or antigen testing, but it may shorten time to the right sampling strategy and reduce diagnostic drift. (dvm360.com)

It also has value for communication. When clinicians can explain that a CT pattern is compatible with blastomycosis, but not definitive, they can better prepare pet parents for the next steps: cytology when accessible lesions are present, urine antigen testing, and careful staging for dissemination. That distinction is important because blastomycosis can look dramatic in the chest, yet treatment decisions still depend on confirming infection and assessing severity across organ systems. Standard references note that treatment typically requires prolonged antifungal therapy, often for at least three months and until active disease is no longer apparent. (merckvetmanual.com)

What to watch: The key question now is whether future multicenter work can connect CT patterns with diagnostic yield, disease severity, prognosis, or relapse risk. If that happens, thoracic CT could become more than a descriptive tool in canine blastomycosis and start to inform triage, sampling priorities, and monitoring in a more standardized way. For now, this study gives radiologists and clinicians a more concrete imaging vocabulary for a disease that still too often masquerades as something else. (eurekamag.com)