NEOPLASTIC DISEASES IN CHICKENS 



23 



Fibrosarcoma 



Tumors found in 16 chickens were diagnosed as fibrosarcoma. These cases 

 art listed in Table 14 together with pertinent data. 



Table 14. — Dat.a. on Sixteen Cases of Fibrosarcoma. 



Case Age 



No. (\\'eeks"l 



Sex 



Primary Site 



Extension or Metastasis 



*K indicates that bird was killed for examination; D, that it died. 



Fibrosarcoma was found most often (six cases) as a primary tumor of skeletal 

 muscle. In two cases metastasis to the visceral organs had occurred, and in 

 another case there was metastasis to the brain. 



The peritoneum was considered the primary site of the tumor in three cases. 

 In two of these the tumors were multiple, small nodular masses scattered over 

 the serosal surface of the mesentery and some of the visceral organs. In one 

 of these cases the entire intestinal tract and mesentery were drawn into a tight, 

 compact mass by a dififuse covering of the peritoneum with fibrosarcoma. In 

 case T 62, a 530-gram encapsulated tumor found in the pelvic cavity, where it 

 displaced the cloaca and rectum to the right, was considered to have originated 

 from peritoneum although its precise point of origin could not be determined. 



Bilateral fibrosarcomas were found in the lungs of one chicken and in no other 

 site. These may represent multicentric points of origin or a spread from one lung 

 to the other. 



In the remaining six cases of fibrosarcoma the primary site of the tumor was 

 the kidney, the liver, the subcutis of the leg, the region of the pharnyx, and the 

 nasal sinus. 



Although there was some A'ariation in the histology of the different cases of 

 fibrosarcoma, the type cell of the tumors was a neoplastic spindle-shaped fibro- 

 blast (Plate VII, Figure 1). 



The majority of birds with fibrosarcoma were killed for examination, but there 

 were onl\- two in which the tumor could be regarded as an incidental finding. 

 In other words, the tumor was usually responsible for the disturbance in health 

 that led to necropsy. The age of birds affected with fibrosarcoma ranged from 



