UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1449 
Washington, D. C. 
October, 1926 
TUMORS OF DOMESTIC ANIMALS 
By Robert J. Fosmad, Associate Pathologist, Pathological Division, Burem 
of Animal Industry 
CONTEXTS 
Page 
Introduction . — 1 1 
Etiology 2 
The constitutional dyscrasia or 
diathesis theory 3 
The mechanical or irritation 
theory 3 
The " embryonal rests " or pre- 
formation theory 3 
The theory of nervous influence- 4 
The parasitic theory 4 
Classification of neoplasms 4 
Classification by nature I clin- 
ical classification i 5 
Classification by structure I his- 
togenetic classification > 6 
Classification by shape (morpho- 
logical classification) 7 
Nomenclature 8 
Connective-tissue neoplasms 8 
Fibroma 8 
Lipoma 10 
Xanthoma 11 
Myxoma 11 
Chondroma 12 
Chordroma 13 
Osteoma 13 
Odontoma 14 
Myeloma 15 
Myoma 15 
Rhabdomyoma 16 
Neuroma 17 
Page 
Glioma 18 
Angioma 19 
Lymphangioma 20 
Lymphoma 20 
Leukemic lymphoma 21 
Pseudo leukemic lymphoma 21 
Sarcoma 21 
Spindle-cell sarcoma 23 
Round-ceil sarcoma 24 
Lymphosarcoma 25 
Alveolar sarcoma 25 
Giant-cell or myeloid sarcoma.- 26 
Osteosarcoma 26 
Melanotic sarcoma 26 
Combinations of sarcomas 27 
Endothelioma 27 
Epithelial neoplasms 28 
Papilloma 28 
Adenoma : 29 
Carcinoma 30 
Squamous epithelioma 31 
Cylindrical epithelioma 32 
Glandular carcinoma 33 
Combinations of carcinoma 35 
Distinction between carcinoma 
and sarcoma 36 
Teratoid neoplasms i teratoma.! 37 
Dermoid cyst 37 
Cysts 38 
Syncytioma 39 
Literature cited 39 
INTRODUCTION 
A tumor is an atypical, abnormal growth of tissue, developing 
without apparent cause, having no function, and growing independ- 
ently of the laws that govern the growth of the body. Until the 
true cause of tumors is known no satisfactory definition can be given, 
as can be seen from the fact that every prominent authority on 
tumors has given a different definition of a tumor, depending on the 
particular angle from which his studies were undertaken. 
Tumors are comparatively common in the domestic animals. They 
are of considerable interest to the veterinary practitioner and of more 
3262°— 26 1 1 
