Pulmonary and Thymic Neoplasia
The most commonly reported neoplasm in the chest of the adult goat is the thymoma (Figure 9.9). Clinical signs of thymoma may include tachypnea, dyspnea, and muffled lung sounds, often unilaterally.
However, some animals develop congestive heart failure (Rostkowski et al. 1985; Hanselaer 1988) or rumen tympany and megaesophagus (Parish et al. 1996). Either radiographic or ultrasonographic findings of a mediastinal mass, which may be cystic, support the diagnosis, although an abscess could have a similar appearance (Hanselaer 1988; Braun et al. 2017). Some affected animals have copious thoracic fluid, which obscures the mass and contains normal lymphocytes. Either epithelial or lymphocytic cells may predominate in the tumor, but the neoplastic cell population is the epithelial cell. Both surgical removal and radiation therapy have been attempted (Hill et al. 2017). In one 8-year-old Alpine wether, a thymoma metastasized to the lungs and spleen (Olchowy et al. 1996). In one instance a 9-year-old Alpine doe developed a paraneoplastic severe exfoliative dermatitis (Byas et al. 2019). Asymptomatic thymomas have been reported in both female and castrated male Saanen goats (Hadlow 1978).Lymphosarcoma produced nodular lesions in the lung parenchyma of 6 of 11 goats in one necropsy study. Only 2 of these 6 animals had been reported to be dyspneic ante mortem (Craig et al. 1986). Another goat with pulmonary lymphosarcoma detected radiographically was initially believed to have pulmonary nocardiosis originating from a chronic mastitis (Rozear et al. 1998). A viral-induced neoplasm of the lung has been discussed under the topic of jaagsiekte (see above). Although rarely reported, other
Figure 9.9 Large thymoma that displaced the heart and lungs caudally. Source: Courtesy of Dr. M.C. Smith.
primary or metastatic lung tumors might be found occasionally in older goats (Ortin et al. 2007).
More on the topic Pulmonary and Thymic Neoplasia:
- Smith Mary C., Sherman David M.. Goat Medicine. 3rd edition. — Wiley-Blackwell,2023. — 976 p., 2023
- Immunosuppression Associated With Leukoproliferative Disorders*