Computed Tomographic Findings in 57 Cats With Primary Pulmonary Neoplasia

Abstract

Primary pulmonary neoplasia is relatively uncommon in cats and generally has a poor prognosis. In this multicenter, retrospective study of 57 cats with pulmonary neoplasia, the most frequent presenting signs were anorexia/inappetence (39%) and cough (37%). The pulmonary tumors were considered to be incidental findings in 9% cats. In computed tomographic (CT) images, primary pulmonary tumors appeared as a pulmonary mass in 55 (96%) cats and as a disseminated pulmonary lesion without a defined mass in two (4%) cats. Most pulmonary tumors were in the caudal lobes, with 28 (49%) in the right caudal lobe and 17 (30%) in the left caudal lobe. CT features associated with pulmonary tumors included mass in contact with visceral pleura (96%), irregular margins (83%), well-defined borders (79%), bronchial compression (74%), gas-containing cavities (63%), foci of mineral attenuation (56%), and bronchial invasion (19%). The mean (range) maximal dimension of the pulmonary masses was 3.5 cm (1.1-11.5 cm). Additional foci of pulmonary disease compatible with metastasis were observed in 53% cats. Pleural fluid was evident in 30% cats and pulmonary thrombosis in 12% cats. The histologic diagnoses were 47 (82%) adenocarcinomas, six (11%) tumors of bronchial origin, three (5%) adenosquamous cell carcinomas, and one (2%) squamous cell carcinoma. In this series, adenocarcinoma was the predominant tumor type, but shared many features with less common tumor types. No associations were identified between tumor type and CT features. Prevalence of suspected intrapulmonary metastasis was higher than in previous radiographic studies of cats with lung tumors.

Nodules and masses are associated with malignant pleural effusion in dogs and cats but many other intrathoracic CT features are poor predictors of the effusion type

“…As the primary author (J.A.R.) had recall bias of the final diagnosis for a small number of cases ( n = 8), owing to those cases being used in prior manuscripts, another board‐certified veterinary radiologist (J.N.S. ), blinded to the final diagnoses in all but one case, also reviewed the CT studies for pleural thickening (presence, location, appearance, and distribution).…”

“…There are fewer studies in veterinary medicine assessing pleural abnormalities on CT in dogs and cats with pleural effusion with some studies simply describing nonspecific thickening of the parietal and/or visceral pleura . Several studies assess pleural abnormalities in more detail, including the assessment of Hounsfield units in different types of pleural effusion and assessing various types of pleural thickening (eg, smooth, irregular, nodular, mass), such as those seen with mesothelioma, carcinomatosis or other malignancies or with infectious pleuritis/mediastinitis associated with pyothorax such as secondary to foreign body migration or bronchopneumonia .…”

Metastatic pulmonary carcinomas in cats (‘feline lung–digit syndrome’): further variations on a theme

“…The lung lesions were reported to have CT characteristics consistent with bronchoalveolar carcinoma or pulmonary infarcts. 8 Although the broad-based appearance of the lesions were thought to be more suggestive of the latter by the radiologist, the presence of lung lesions, muscle lesions and a history of ATE were most consistent with atypical lung–digit syndrome. 6 Neither pulmonary arterial emboli nor distal aortic emboli could be visualised in the CT scans after intravenous iohexol administration.…”

Associations between respiratory signs and abnormalities reported in thoracic CT scans of cats

“…, Aarsvold et al . ). Being a cross‐sectional imaging modality, CT eliminates the problem of superimposition that affects radiography and therefore enables clearer depiction of internal anatomy and morphological abnormalities that alter anatomy.…”