22 MASS. EXPERIMENT STATION BULLETIN 391 



2. T 25 L Swelling of the right eye and excessive lacrimation was noted 

 in a 32-week-old hen. The bird was killed for examination. A tumor mass in 

 the right nasal passage and sinus was found to be responsible for the swelling 

 of the eye. The tumor was irregular in outline, firm, and contained several 

 small cysts. The cysts were lined with columnar epithelium and probably rep- 

 resented portions of the respiratory mucosa pinched off by growth of the fibroma. 



3. T 253. A 28-week-old pullet was noted as slightly dull and submitted 

 to the laboratory for examination. Upon necropsy, a large tumor weighing 190 

 grams was found in the wall of the large intestine about 2.5 cm. from the vent. 

 The tumor encircled the intestine, though the lumen was eccentric in position 

 (Plate \T, Figure 1). The substance of the tumor was very tough and fibrous 

 (Plate VI, Figure 3). 



4. T 293. A male, killed for examination at the age of 15 weeks, was found 

 to have a slight swelling of the region over the right nasal sinus. A tumor meas- 

 uring 20 X 12 X 10 mm. was found in the nasal sinus displacing the structures 

 lateral to it. 



5. T 1327. A one-year-old pullet died from cannibalism. In the left ventricu- 

 lar wall of the heart was a firm, gray mass measuring approximately 3X2X1 

 cm., which proved upon section to be a fibroma (Plate VI, Figure 2). A Van 

 Gieson's preparation was made of a section of the tumor to eliminate the possi- 

 bility of the tumor's being of muscular origin. The reaction was characteristic 

 of fibrous tissue. A record of the egg production of this bird was available. 

 It had laid only 32 eggs during a productive life of 98 days, which gives a produc- 

 tion index of 0.326. This is lower than the average for the flock. (See section 

 on Lymphocytoma for discussion of the production index.) The last egg was 

 laid 80 days previous to the death of the bird. 



It is of interest to note that in two of the five cases, the fibromas were located 

 in the nasal sinus. In one case of fibrosarcoma, also, the tumor was in the nasal 

 sinus. These facts suggest that the nasal sinus is a likely site for the develop- 

 ment of fibroblastic tumors, although a survey of the literature on avian tumors 

 does not bear out the suggestion. 



Although fibromas are ordinarily considered benign, the tumor was the primary 

 reason for examination in four of the cases and represented the principal path- 

 ological finding. 



Myxoma 



Two cases of m}"xoma were found in the collection. A short description of 

 each follows. 



1. T 81. A 6-month-old Rhode Island Red male was found dead. Its ab- 

 domen was filled with a 717-gram tumor attached to the left kidney. The surface 

 of the tumor was smooth, glistening, and yellow-white in color. On cross section 

 the tissue of the tumor was spongy and cystic and much distinctly mucinous 

 fliuid could be pressed from the cut surface. Most of the left kidney was de- 

 stroyed by the tumor. The tumor was composed of a ver}- loose arrangement 

 of small stellate cells with anastomosing processes. No metastatic or implanta- 

 tion nodules of tumor could be found. 



2. T 197. A 7-week-old Barred Plymouth Rock male was submitted for 

 examination because of swelling in the region of the left eye. The bird was killed 

 and examined. A yellow-white, irregularly lobulated tumor was found in the 

 orbital cavity, which caused protrusion of the left eye. The histology of the tumor 

 was similar to that of case T 81. No other pathology was found. 



The morphology and mucin production of the type cell of these two tumors 

 clearly indicates their embryonal character (Plate VI, Figures 4 and 5). Although 

 myxosarcomas (malignant tumors of the same t\pe cell) ha^e been found in 

 the chicken by different observers (Olson 20), no additional cases were found in 

 the present sur\ey. 



