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Transmissible Venereal Tumor 993

Transmissible Venereal Tumor Bonus Material Client Education
Online
Sheet
VetBooks.ir Diseases and Disorders
• Clinical signs of TVT typically last 40-100
BASIC INFORMATION
days but may last longer, depending on the • Cell origin of TVT is unknown but is
presumed to be an undifferentiated round
Definition tumor size and location, immune status of cell neoplasm of histiocytic origin.
A contagious, neoplastic disease transmitted the animal, and occurrence of secondary • Chromosome number of tumor cells is 59 ±
by transplantation of viable tumor cells during bacterial infections. 5, whereas the normal canine complement
coitus is 78.
PHYSICAL EXAM FINDINGS • Leishmania spp amastigotes have been isolated
Synonyms • Nodular lesions in the external genitalia from TVT tissue, which could represent an
Canine condyloma, contagious lymphoma, • Solitary or multiple masses progressing to alternative route of venereal transmission of
contagious venereal tumor, infectious sarcoma, cauliflower-like, papillary, multilobulated, leishmaniasis.
Sticker’s sarcoma, transmissible venereal or pedunculated masses
sarcoma, venereal granuloma, TVT • Appearance is typically gray or pinkish gray. DIAGNOSIS
• Texture is firm but friable; masses bleed
Epidemiology easily when manipulated, resulting in genital Diagnostic Overview
SPECIES, AGE, SEX bleeding in both sexes. The diagnosis is suspected based on history/
• Species: canids (dogs, foxes, coyotes, jackals) • In the oronasal presentation, epistaxis and presence of a hemorrhagic mass on the genital
• Age: mostly young, sexually active animals; frequent sneezing with epistaxis, halitosis, mucosa. Confirmation is achieved with cyto-
average age of 4-5 years ptyalism, dyspnea, loss of teeth, and ulcer- logic assessment of impression smears and a
• Sex: both sexes; females > males ative lesions in gingivae and palate biopsy (which may serve to debulk the mass).
• In the skin, nodular masses may be ulcer-
GENETICS, BREED PREDISPOSITION ated, and regional lymph nodes may be Differential Diagnosis
Higher prevalence in mixed-breed dogs enlarged. • Tumor type is suspected by the history,
location, and appearance of the mass.
RISK FACTORS Etiology and Pathophysiology • Especially when there is no evidence of a
• More commonly occurs in free-roaming, • Transmitted by coitus; affecting mainly primary genital tumor, TVT can be confused
sexually active dogs external genital organs, and spreading to with other round cell tumors such as mast
• Grows more rapidly in neonatal or immu- internal genitalia cell tumor, histiocytoma, and lymphoma.
nosuppressed dogs • Transmitted more easily if there are abrasions Also to be considered are malignant mela-
or breaks in the integrity of the mucosal noma, squamous cell carcinoma (SCC), and
CONTAGION AND ZOONOSIS surface fibrosarcoma.
By definition, transmissible venereal tumor • Social behavior (e.g., licking/sniffing affected • Clinical signs may be similar to those found
(TVT) is contagious among members of areas) can produce extragenital TVT in the with prostatitis, estrus, urethritis, and cystitis.
the family Canidae. It has not been identi- skin and eyes and in oral and nasal cavities.
fied as a zoonotic disease, although personal • Metastasis is rare, but when it occurs, it Initial Database
protection apparel (e.g., exam gloves) is recom- affects regional lymph nodes, subcutaneous Cytologic exam of impression smears stained
mended when examining and treating TVT tissues, abdominal and thoracic viscera, brain, with Wright’s or new methylene blue reveal
lesions. pituitary, spleen, and kidneys. Metastatic homogeneous sheets of round to oval cells
disease can also occur without the presence with prominent nucleoli and a small amount
GEOGRAPHY AND SEASONALITY of a primary genital tumor. of cytoplasm with multiple mitotic figures.
• Worldwide distribution
• Greatest prevalence in tropical and subtropi-
cal urban environments
ASSOCIATED DISORDERS
• Urinary tract infections (UTIs) due to TVT
masses in the vestibulovaginal junction
(females) and phimosis (males), with inability
to extrude the penis from the prepuce. Both
conditions interfere with urination.
• Tumors are easily traumatized and ulcerated;
secondary bacterial infection is common.
Clinical Presentation
DISEASE FORMS/SUBTYPES
Genital and extragenital forms
HISTORY, CHIEF COMPLAINT
• Initial persistent or intermittent bloody
genital discharge (often foul smelling),
constant licking, genital malformation, or
swelling TRANSMISSIBLE VENEREAL TUMOR Cytologic exam of a TVT on impression smears stained with Wright’s
• Eventually, masses can be seen protruding reveal homogeneous sheets of round to oval cells with prominent nucleoli and a small amount of cytoplasm
from the vulva or penis. with multiple mitotic figures.

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