CT patterns in canine lung metastases may point to primary tumor type

A new retrospective study in Veterinary Radiology & Ultrasound suggests thoracic CT features may help clinicians narrow the likely primary tumor type when dogs present with pulmonary metastatic nodules. The study, published in March 2026 by Federica Rossi, Mirko Mattolini, Valentina Meucci, and Simonetta Citi, reviewed CT scans from 271 dogs with pulmonary metastases, including a 126-dog subgroup with both the primary tumor and metastases confirmed. Across six tumor histotypes, the authors found statistically significant imaging patterns tied to tumor type, including ill-defined margins and cavitary lesions in carcinomas, incomplete mineralization in bone sarcomas, and a higher number of nodules plus halo and SPLASH signs in hemangiosarcoma. Larger nodules, air bronchograms, and thoracic lymphadenomegaly were associated with histiocytic sarcoma. (pubmed.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the findings could make CT more useful not just for staging, but also for prioritizing differentials when the primary cancer isn't obvious, when a dog may have more than one possible primary, or when pulmonary nodules can't be safely sampled. That may be especially relevant in referral oncology and radiology workflows, where treatment planning often moves forward before tissue confirmation is possible. The paper also builds on earlier breed- and tumor-specific CT work, including a 2024 study showing that pulmonary and extrapulmonary CT findings can help orient clinicians toward metastatic hemangiosarcoma. (pubmed.ncbi.nlm.nih.gov)

What to watch: The next step is whether these histotype-linked CT patterns can be validated prospectively and incorporated into more standardized imaging-based decision support for canine oncology. (pubmed.ncbi.nlm.nih.gov)