382 Surgical Diseases and Surgery of the Dog 



pedunculate. Having removed the growth, I submitted it to Pro- 

 fessor Adami, who pronounced it a fibro-adenoma undergoing what 

 could not be regarded as otherwise than an early cancerous change. 

 In an instance recorded by McFadyean a carcinoma appeared 

 to have developed as a secondary growth from an anal adenoma. 

 But in no part of the body are such striking instances of progressive 

 malignancy afforded as in the mammary gland. While true malig- 

 nant adenoma of these glands is far from uncommon, the usual 

 type of growth met with in this region is fibro-adenoma exhibiting 

 a modified malignancy with proneness to recur after ablation but 

 with a tardy tendency towards general dissemination. This recur- 

 rence may take place in the area from which the initial tumor has 

 been removed by continued growth of left-over particles, or it may 

 take place in the neighboring mammae owing to a latent tendency 

 towards this form of tumor- formation existing in the mammary 

 glands as a whole, and which may break out in individual glands 

 at different times, the growths forming in the later years of the 

 animal's life being more inclined to exhibit malignant character. 

 In an instance which I observed a firm mammary tumor appeared 

 in a Skye terrier female at the age of eight years. After reaching 

 a moderate size it remained quiescent for seven years, when it 

 suddenly commenced to enlarge at an alarming rate in addition 

 to giving birth to numerous secondary growths in the neighbor- 

 ing glands. It proved on examination to be carcinoma. In. the 

 middle of the last century Leblanc observed this phenomenon and 

 referred to "simple hypertrophic enlargements" as being commonly 

 mistaken for cancer. He made some consecutive examinations of 

 recurring mammary tumors and noticed a gradual transition into 

 malignancy. The first growth removed was found to be simple 

 adenoma, but malignant characteristics become more and more ac- 

 centuated according as the recurrence increased in frequency. 

 Froehner believes that the majority of such tumors are malignant 

 in character, while McFadyean has expressed the view, after exam- 

 ining a series of these growths that the commonest form of en- 

 largement is of the nature of a fibrous induration, the groups of 

 cells scattered through the fibrous stroma being in reality the 

 compressed remains of the glandular acini, the compression re- 

 sulting from the formation of new connective tissue. 



There is a specimen in the Army Medical Museum at Wash- 



