A Review of Primary Lung Tumors in the Dog and Cat

Abstract

Primary pulmonary carcinomas are being encountered with increasing frequency in older dogs and cats. The most common presenting complaint in the canine is a nonproductive cough of several weeks' duration, but many affected animals have no abnormal clinical signs in the early stages of the disease. A solitary mass that arises from a single focus in the peripheral pulmonary tissue is the most frequently observed radiographic sign of a primary lung tumor. Often a definitive diagnosis can be made only following thoracotomy with removal or biopsy study of the neoplastic tissue. A classification system based on the prevailing histologic pattern may then be used to categorize most primary lung neoplasms as adenocarcinomas, squamous cell carcinomas, anaplastic carcinomas, or bronchioloalveolar carcinomas. Adenocarcinomas are most common in the dog and cat. Only the neoplastic cell type and the presence or absence of metastatic disease have been found to be of value as prognostic indicators. Following wide surgical resection of the pulmonary mass, dogs with pulmonary adenocarcinomas are reported to have a longer mean survival time than animals with other types of primary lung carcinomas.

Lung

“…[60][61][62] Torsion can occur spontaneously, 60,63 but most reported cases have an underlying respiratory disease identified or suggested, e.g., feline asthma, 64 or it may be associated with pleural effusion, including chylothorax. 13 Cavitation is rarely described, which is in contrast to that described in primary neoplasms. 57 Most pulmonary lesions (92%) are generalized 57 but metastatic nodules tend to be in the middle or peripheral portions of lung and typically consist of several large masses and a number of smaller masses, which are generally smaller and well circumscribed compared with primary masses.…”

“…16 The limitations of BAL include failure to sample a representative area of disease, low cellularity, the difficulty sometimes encountered differentiating neoplasia from epithelial hyperplasia, the presence of marked inflammation Box 47-2 Differential diagnoses for common radiographic and computed tomographic patterns of lung disease 2,[9][10][11][12][13][14][15] Solid radio-opaque pulmonary mass 16 The limitations of BAL include failure to sample a representative area of disease, low cellularity, the difficulty sometimes encountered differentiating neoplasia from epithelial hyperplasia, the presence of marked inflammation Box 47-2 Differential diagnoses for common radiographic and computed tomographic patterns of lung disease 2,[9][10][11][12][13][14][15] Solid radio-opaque pulmonary mass …”

The Respiratory System

“…109,111 The typical radiographic findings are a solitary nodular lesion involving a single lung lobe 111 and infrequently multiple nodules or diffuse involvement of one or more lung lobes. The right caudal lung lobe is most commonly affected (Figure 9-11).…”

Immunohistochemistry characterization of a bronchioloalveolar carcinoma mixed subtype in cat

“…In contrast, is an infrequent found in domestic animals (2,11). Spontaneous lung tumors are more frequently in dogs, cats and sheep (6,8). A betaretrovirus is responsible for pulmonary adenocarcinoma in sheep (10), while, in the dogs and cats this neoplasia was not related to any infectious etiology (5,6,8).…”

“…Spontaneous lung tumors are more frequently in dogs, cats and sheep (6,8). A betaretrovirus is responsible for pulmonary adenocarcinoma in sheep (10), while, in the dogs and cats this neoplasia was not related to any infectious etiology (5,6,8). In dogs and cats, lung tumors occur as a sporadic geriatric disease and they have variety and clinical signs often similar to many other respiratory diseases, such as anorexia, weight loss, wheezing, lethargy, dyspnea, tachypnea, ataxia, hemoptysis, and coughing (6,8,9).…”