Comparative Pathology of Lymphocytic Malignancies 169 



cytic malignancies in the dog (as well as in most other species). Bloom and 

 Meyer 3 rising sections and imprints have classified twenty canine cases into 

 lymphoblastic, lymphosarcoma cell, lymphocytic, and mixed cell types. We 

 have seen a lew cases which could he related histologically to the giant 

 follicular lymphoblastoma of man. A few canine cases simulating Hodgkin's 

 disease of man have also been reported.-" At this time no clear-cut correla- 

 tion is evident between the various histologic or cytologic manifestations 

 and the biologic course of the disease. 



Fig. 13-6. Canine malignant lymphoma, ventral aspect ol mandibular 

 region with skin reflected. All lymph nodes are greatly enlarged. A male 

 mongrel terrier dog, 12 years ol age. (Courtesy of Angell Memorial 

 Animal Hospital.) 



The gross lesions in the dog are of interest, particularly in comparison 

 with those of the cat and other species. As in all species, it is often difficult, 

 if not impossible, to determine the "primary" site of the lesions. More 

 often than not it appears that several organs may be invaded by malignant 

 lymphoid cells almost simultaneously. This generalized manifestation most 

 frequently affects the lymph nodes. In some cases one organ may be par- 

 ticularly affected and may be greatly enlarged before other organs are 

 seriously invaded. This results in a lesion which is foremost when the 



