Pig carcass with nodular lesions in the pleura and viscera
In a male, 6 months old, pig carcass, multiple whitish nodular lesions were observed in the lungs, parietal pleura, diaphragm and in the liver.
Although teh appearance was not of caseous necrosis the inspectors suspected of a tuberculosis case.
The histopathological study showed that it was a malignant round cell neoplasia: lymphosarcoma. In pigs, tuberculous lesions have a proliferative nature, rather than necrotic and, macroscopically, may resemble the aspect of a neoplasia. Therefore, it was necessary to rule out that it was an outbreak of tuberculosis. Tuberculous lesions in pigs can be caused by mycobacteria within the M.tuberculosis complex and M.avium.

Image of Histopathology of the liver showing a proliferation of round cells (upper right, bluish). At higher magnification (inset) one can observe neoplastic cells.
Thanks for your comment Martín, we had a few cases of M.avium in pigs a couple of years ago:
http://www.cresa.cat/blogs/sesc/lesions-granulomatoses-disseminades-en-canals-de-porci/?lang=en
Then the suspected origin of the infection was the feed fed to the animals, which was the dame in the different farms that has cases.