The lungs are a common site of metastasis, with recognized computed tomography (CT) features of different histotypes in humans. Little information is available for dogs. This retrospective, observational study compared the CT characteristics of pulmonary metastases from different primary cancers in dogs. CT studies of two groups of dogs with primary neoplasia and pulmonary metastases were reviewed. Group 1 (n = 271) included dogs with a definitive diagnosis of either the primary neoplasia, the metastases, or both, and Group 2 (n = 126) was a subgroup with both diagnoses confirmed. Six primary tumor histotypes were analyzed: epithelial cancer, bone sarcoma, soft tissue sarcoma, melanoma, hemangiosarcoma (HSA), and histiocytic sarcoma. Recorded features included nodule number, distribution, shape, size, margins, attenuation, pattern of enhancement, and the presence of other abnormalities. For both groups, CT features statistically correlated with tumor histotype (p 1 cm), air bronchograms, and thoracic lymphadenomegaly in histiocytic sarcomas and incomplete nodule mineralization in bone sarcomas. CT features of lung metastases help prioritize neoplasia histotype in dogs, aiding diagnosis if the primary tumor is not obvious, if two cancers are potential origins of the metastases, or when the pulmonary nodules cannot be sampled.
Rossi et al. (Sun,) studied this question.