42 MASS. EXPERIMENT STATION BULLETIN 391 



conclusion that the epithelial fraction of carcinoma leiomyomatosum was the 

 primary element of neoplasia which was capable of stimulating a local prolifera- 

 tion of pre-existing muscle tissue. Thus the mixed tumor did not spread as such, 

 but only the epithelial part was capable of growing when transplanted to a new 

 site. Nodular foci on the serosa composed of muscular tissue only as well as 

 nodules of mixed tissues were found in another case by Jackson. He explaine:! 

 the presence of pure muscle tumors b\ endowing the muscular elements with a 

 greater growth energy to the extent that the epithelial elements although orig- 

 inally present were later overgrown and destro\ed. 



The seven cases of carcinosarcoma here described are different from the cases 

 discussed by Jackson in that the smooth muscle in the mixed tumors was small 

 in amount. The leiomyoma of the mesosalpinx in four of the cases appeared to 

 be identical with that found in old hens with a history of heavy egg production. 

 It does not seem logical to explain their origin as due to a stimulus from an im- 

 plant of carcinoma which later regressed, for other nodules of pure muscle tissue 

 did not occur. Although in two instances a small amount of epithelial tumor 

 was found at the edge of the leiomj'mas of the mesosalpinx, these can not be re- 

 garded as mixed tumors but would appear to represent implants of the carcinoma 

 on the serous covering of the leiomyoma. Leiomyoma of the mesosalpinx in 

 birds also affected with another type of tumor is not unusual. Among the 14 

 cases of carcinoma in this collection were two such instances (T 16 and T 294, 

 Table 15). Two similar cases are listed in Appendix C of the monograph by Jack- 

 son (13). 



Use of the term carcinosarcoma for this group of tumors may be open to ques- 

 tion. The presence of smooth muscle and connective tissue in an apparent stage 

 of neoplasia would exclude the cases from the classification of scirrhous car- 

 cinoma. The more abundant amount of connective tissue elements does not 

 permit application of Jackson's term "carcinoma leiomyomatosum." Joest and 

 Ernesti (14) described a case which may be similar to these as "sarcoma car- 

 cinomatodes." For the present at least the term carcinosarcoma seems to be 

 appropriate t3 indicate a tumcr made up of mixed elements in which the epithelial 

 part as well as the connective tissue and muscular parts have assumed a state 

 of malignancy. 



Teratoma 



One case of teratoma was found. 



1. Case T 307. A year-and-a-half-old male was killed for examination, 

 and before death had been noted to be weak, depressed, and inactive. The 

 posterior half of the left testis was represented by a large mass measuring 13 X 

 10 X 7 cm. and the entire structure weighed 606 grams (Plate I, Figure 5). The 

 tumor was well encapsulated and had a glistening irregular surface roughened 

 by nodules. The cut surface of the tumor showed many small scattered areas of 

 dry necrosis. In general the color was gray-white. Many small cysts up to 

 2 mm. in diameter were noted. Small patches of cartilagenous tissue could be 

 felt when the finger tips were rubbed over the cut surface. The left vas deferens 

 and epididymis could not be located in the region of the tumor. The right gonad 

 was normal. The histolog>' of the tumor was extremely variable with a bizarre 

 mixture of various types of tissue. There were many small islands of well-de- 

 veloped cartilage, numerous irregularly formed acini lined with columnar epi- 

 thelium. Some of these were distended with granular material and the cells 

 lining such areas had vacuoles (probably secretory) in their cytoplasm. A con- 

 siderable portion of the tumor was made up of connective tissue cells varying 

 in form from slightly differentiated stellate cells to spindle-shaped fibroblasts. 



