NEOPLASTIC DISEASES IN CHICKENS 29 



In the case of niultiple papillomatosis, numerous small gra\- nodules, some 

 hemorrhagic, were found on the mucosa of the crop and esophagus adjacent to 

 the crop. The wall of the crop was somewhat thickened, about 6 mm. across 

 in the thicker portions. The lesions consisted of papiUar\- projections covered 

 with stratified squamous epithelium (Plate IX, Figure 1). There was in addition 

 a polyblastic infiltration in the submucosa. The chicken was in fair flesh and the 

 only symptom of disease was a slightly distended crop. 



A feather follicle adenoma had been noted as a swelling on the head of a chicken 

 for one month before the bird was killed. The swelling had been breaking open 

 and bleeding at different times (during the interval between the time it was 

 first noted and necropsy). On section, the swelling was found due to a mass of 

 well-vascularized, encapsulated, gelatinous tissue measuring 10 mm. in diameter 

 by 6 mm. thick, which was confined to the subcutis and attached to the skin. 

 Histologically the mass was composed of cells arranged in a syncitium and re- 

 sembled very much the cells found at the base of feather follicles. 



A foetal adenoma of the thyroid was found in a chicken killed because of 

 infection with infectious laryngotracheitis. The left thyroid measured 40 X 

 35 X 25 mm. and contained a few cysts filled with dark green semi-fluid material. 

 The bulk of the affected thyroid was foimd to be made up of foetal thyroid tissue, 

 small, compressed acini of cells with no lumen (Plate VIII, Figure 2). There 

 were a few dilated acini whose lumen contained pink-staining colloid mixed with 

 much cellular debris. The right th\roid was normal. A small melanoma was also 

 found in this case near the base of the tongue. 



In the majority of cases of epithelial neoplasia examined, the chickens were 

 killed. The average age was 67.1 weeks at the time of necropsy although there 

 was considerable variation (range from 12 to 258 weeks). Neoplasia was an in- 

 cidental finding in seven cases, the majorit> of which were relativcK' \outig 

 birds. One bird in this group was 228 weeks old at the time of examination; 

 but if this bird is disregarded, the average age of the birds in which neoplasia 

 was an incidental finding was only 28 weeks. In 10 birds the tumor was the 

 principal reason for examination, and the average age of this group was consid- 

 erably older (54.2 weeks, with elimination of one bird which was 258 weeks old). 



Legend for Plate XII 



Figure 1. S 2,5.'{. Carcinosarcoma. A loop of intestine has been spread out to show the heavy, 

 diffuse implantation of tumor on the serous surface of the mesentery. 



Figure 2. Case 1898. Leiomyoma in mesosalpinx. The entire oviduct and ventral mesosal- 

 pinx together with the nodular tumor mass is so arranged as to illustrate their relationship. This 

 specimen is a relatively small tumor. 



Figure 3. Q 1621. Carcinosarcoma. The histological section was prepared from an implant 

 of the tumor on the serosa of the mesentery of the pancreas. Many irregular acini of epithelial 

 cells are apparent. The malignant appearance of the stroma of the connective tissue elements is 

 also obvious. Magnification X 8.5. 



Figure 4. T 141. Rhabdomyoma in muscle of thigh. Both loose and compact arrangement 

 of the tumor cells is evident. Several giant cells of the Plasmodium type are scattered about in 

 the loosely arranged portion. The tumor metastasized to the wall of the intestine. Magnification 

 X 140. 



Figure 5. T 170. Leiomyoma of mesosalpinx. The cells of a single bundle are arranged in 

 a parallel fashion. The pale staining elongate nuclei with rounded ends may be noted. Mag- 

 nihcation x 285. 



