Prevalence of pulmonary nodules suggestive of metastasis at presentation in dogs with cutaneous or subcutaneous soft tissue sarcoma.

OBJECTIVE: To investigate the prevalence of pulmonary nodules suggestive of metastasis at the time of initial presentation in dogs with cutaneous or subcutaneous soft tissue sarcomas (STSs) and no previous related thoracic diagnostic imaging. ANIMALS: 146 client-owned dogs with a cutaneous or subcutaneous STS. PROCEDURES: Medical records were retrospectively searched to identify dogs with STSs that underwent initial thoracic diagnostic imaging when presented for referral examination between September 2014 and March 2018. Data collected included patient and tumor characteristics. Results were evaluated for dogs grouped on the basis of variables of interest (eg, STS grade, duration, or history). RESULTS: Initial thoracic imaging was performed with CT (131/146 [89.7%]) or radiography (15 [10.3%]). Although the presence or absence of pulmonary nodules suggestive of metastasis on thoracic imaging was uncertain in 9 dogs, it was certain in the remaining 137 dogs, with nodules present in 16 (11.7%) dogs (5/77 [6%] with grade 1 STSs, 2/36 [6%] with grade 2 STSs, and 9/24 [38%] with grade 3 STSs). The odds of such pulmonary nodules being present on initial examination were higher (OR, 10.8 and 3.14, respectively) for dogs with grade 3 STSs (vs grade 1 or 2 STSs) and for dogs with an STS duration > 3 months (versus ≤ 3 months). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that pulmonary staging was a low-yield diagnostic procedure for dogs with grade 1 or 2 cutaneous or subcutaneous STSs, especially when tumors had been present for ≤ 3 months.