Imaging Diagnosis of Asymptomatic Incomplete Lung Lobe Torsion in a Dog

초록

Lung lobe torsion (LLT) in dogs is usually an acute, life-threatening emergency that necessitates immediate surgical intervention. However, subclinical or incomplete cases of LLT are rarely documented in veterinary literature. This report details a 7-year-old neutered male mixed-breed dog (10.8 kg) that was presented for evaluation of a left axillary nodule. The physical examination and laboratory tests were unremarkable. Thoracic radiography incidentally revealed curvilinear mineral opacity in the right middle lung lobe (RML). Further investigation using computed tomography (CT) showed caudodorsal displacement and truncation of the RML bronchus, a reduced diameter of the RML pulmonary vessels. Given the absence of clinical symptoms and the imaging findings suggestive of residual vascular supply, a presumptive diagnosis of asymptomatic incomplete LLT was made. The patient was managed conservatively. Follow-up CT scans at 2 and 8 months, along with serial radiographs up to 16 months, demonstrated no significant progression or parenchymal necrosis. As of 37 months post-initial presentation, the patient remains asymptomatic. This case demonstrates that such a phenotype can exist as a stable, subclinical finding in dogs, suggesting that serial follow-up can be a viable conservative option in hemodynamically stable, asymptomatic patients without parenchymal consolidation.

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