Cytological confirmation and chemotherapeutic management of canine transmissible venereal tumor: A case report

Introduction

Canine transmissible venereal tumor (CTVT), also referred as Canine Transmissible Venereal Sarcoma (CTVS), Venereal Granuloma (VG), Infectious Granuloma, Infectious Sarcoma, Contagious Lymphosarcoma, Sticker's Sarcoma, Canine Condyloma and Infectious Sarcoma, is a mesenchymal origin reticuloendothelial (histiocytic) tumour of both male and female dogs (Brown et al., 1981; Anusha et al., 2022) [4,3] . CTVT is commonly encountered in 1-5 years of age group (Subapriya et al., 2025) [16] . It is a highly contagious tumour, which affects external genitalia, most commonly the base of the penis or prepuce in males and the vagina or labia in females (Anusha et al., 2022; Reddy et al., 2022) [3,11] . Though it can get transmitted horizontally through licking, bitting even sniffing of the affected area, venereal route is the most common (Nak et al., 2005; Anusha et al., 2022) [9,3] . Frequent bloody discharge from affected area, serosanguinous secretions with intense odour, ulceration and possibly necrosis of the affected area with deformity etc. are clinically evident in a positive case (Abeka, 2019; Bulhosaa et al., 2020; Anusha et al., 2022) [20,6,3] . Definitive diagnosis of CTVT is based on history, clinical presentations, cytological and histological findings (Abeka, 2019) [20] . However, Polymerase Chain Reaction (PCR) and Immuno-Histochemical evaluation can aid the diagnosis (Moulton 1978, Richardson 1981, Daleck et al. 1987) [7,12,5] . Here in this communication, a cytology aided diagnosis of CTVT was reported with a successful chemotherapeutic regimen of Vincrystine sulphate in combination with Ivermectine for the first time from this part of the country.

Materials and Methods

Case History & Clinical findings Two 1.5 (Case 1) and 3 (Case 2) years old semi-domesticated cross bred male dogs were reported to outpatient department of Veterinary Clinical Complex with previous episodes of frequent preputial bleeding irrespective of urination and noticeable swelling at the base of penis. Anamnestic data revealed that both the dogs had free access to street dogs indicative of semi-domestication and the said condition existed since last two months. No changes in appetite and other behavioral activity could be noted by the owner. Clinically the dog had 102̊ F & 101.3̊ F body temperatures, 78 & 83 beats/minute (bpm) pulse and 20 & 18 bpm respiration respectively for case 1 & 2. Physically multilobular or cauliflowers like tumorous growth were found at the base of penis upon penile exposure for both dogs (Case 1 & 2) indicative of CTVT (Fig. 1: Day 0, red arrow).

Cytological study

For cytological verification samples were taken from the lobular tumorous mass by imprint method. The methanol fixed smears were subjected for Giemsa staining method and microscopic examination under 100X magnification. Based on History, clinical & physical findings as well as cytological confirmation both cases were diagnosed as CTVT and subjected to same chemotherapeutic regimen as stated below.

Treatment

Vincrystine (Cytocristin Aqueous: Cipla Ltd.'s) injection (inj.) was administered @ 0.025 mg per Kg body weight (bwt) intravenously (IV) at 7 days interval for four occasions with Normal Saline in combinations with Ivermectine (Mectin: Alembic Pharmaceuticals Ltd.) inj. @ 200 µg per Kg bwt subcutaneously (SC) on each day of Vincrystine inj. To counter act the chemotherapeutic side effect proton pump inhibitor (ppi) Pantoprazol inj. (Omirise P40: Corise Healthcare Pvt. Ltd.) @ 1 mg per Kg bwt IV was administered 30 minutes before the above protocol. As a supportive therapy Ocoxin Syrup (Vivaldis Health and Foods Pvt. Ltd.), Sharkoferrol Pet syrup (Alembic Pharmaceuticals Ltd.), Hepamust Pet syrup (Pet-Mankind Pharma. Ltd.) and oral proton pump inhibitor were prescribed for a period of one and half month & one month respectively. During this period owners was advised to monitor the animal carefully and to provide easily digestible palatable food with adlibitum water.

Results and Discussion

Gradual reduction of the size & shape (Fig. 1: Day 15, red arrow) followed by complete cessation of the cauliflowers like growth (Case 1 & 2) were observed with uneventful clinical recovery after completion of treatment protocol for both animals (Fig. 1: Day 45, red arrow). Cytological evaluation showed presence of discrete round cells containing moderate amount of bluish cytoplasm, acentric nucleus and distinct borders (Fig: 2). In few cells characteristic pounched out cytoplasmic vacuolation pattern with spherical nuclei and chromatin granules were seen (Fig. 2). Cytological examination also revealed characteristic round cells, distinct borders with slightly acidophilic finely granular cytoplasm containing delicate vacuoles. Nuclei containing delicate chromatin were round to oval in shaped, eccentrically placed.

Discussion

Clinical presentation tentatively diagnosis CTVT however, cytological evaluation as confirmatory diagnosis is must (Bulhosaa et al., 2020; Anusha et al., 2022) [6,3] as implemented here in this case. Both clinical and cytological findings of our study were in accordance with previous reports (Priyadarshini et [6,11,19] . These effects were due to the inhibition of P- [3,6,11,19] . Moreover, anti-neoplastic efficacy of Ivermectine was also reported (Kaur et al., 2021) [10] . CTVT is a horizontally transmitted venereal tumour that occurs regardless of sex and not only limited to external reproductive organs but also metastasizes to other tissue especially in immunocompromised hosts ( [18,11,19] [18,6,1,19] ; therefore, to maintain adequate immune response and healthy liver function anti-oxidant, immune supportive & liver tonic were supplemented to the prescription. Inapt domestication or semi domestication leading to physical contact of susceptible host to infected one leading to coitus is the main culprit of transmission among the household pet population (Subapriya et al., 2025) [16] . Therefore, averting the contact of domesticated pets to street dog population as well as a safe breeding management is the need of the hour for prevention of the malady.

Conclusion

As a final point authors would like to state that, therapeutic management of CTVT with Vincrystine in tandem with Ivermectine could bring early uneventful recovery when managed with good supportive therapy and feeding practice.

References

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