Soft tissue tumours in German Shepherd dogs: An incidence

Introduction

A neoplasm is considered benign when there is a localized, uncontrolled increase in cell numbers without invasion into surrounding tissues. In contrast, a malignant neoplasm is characterized by abnormal cells that invade nearby normal tissues and may spread to distant sites in the body through metastasis (Kitchell and Dervisis, 2010) [8] . The causative agent of tumours in dogs is multifactorial (Arya et al., 2018) [1] , which includes the participation of sex hormones, genetic, oncogenic viruses, immunological factors, environmental factors, and carcinogens as well. Most researchers believe that cancer results from genetic derangement in a cell that retains replicative potential (Roshini et al., 2013) [10] . The highest incidence rate of neoplasia in females is found in the mammary gland and in the skin. Similarly, the majority of the neoplasms in males are found in the skin, oral cavity and digestive organs. While the majority of tumours in the digestive and respiratory system are malignant, the majority of tumours in the ocular system are benign (Choi et al., 2016) [5] .

Materials and Methods

This study was conducted on 40 clinical cases of different soft tissue tumours that were presented for surgical management at the Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry, Kamdhenu University, Junagadh, between April, 2024 to May 2025. To assess the epidemiological characteristics of soft tissue tumours, data on age (categorized as 0 to ≤ 3 years, 4 to 8 years, 8 to 12 years, and above 13 years), sex (male and female), types of tumours, location of tumours, and histopathology were also gathered and analysed.

Results and Discussion

Overall Incidence A total of 40 cases of various neoplastic conditions were reported between April, 2024 to May, 2025 at the Veterinary Clinical Complex, Kamdhenu University, Junagadh. Out of these, 13 cases were found in German Shepherds, which were further investigated.

Age-wise Incidence

Among the 13 German Shepherd dogs diagnosed with soft tissue tumours, the highest incidence was observed in the 9 to 12 years age group, accounting for 7 cases (53.85%) (Table 1). This was followed by the 4 to 8 years group with 6 cases (46.15%); the over 12 years group and the under 4 years group had 0 cases in this study. Similar findings have been reported by Da Silva et al. (2018) [6] and Bhimani et al. (2024) [3] , all of whom observed that years. Witsch et al. (2010) [14] explained that ageing increases the likelihood of genetic mutations and the accumulation of tumour-promoting factors, raising the probability of mammary gland tumour development in older dogs.

Sex Wise Incidence

The incidence of soft tissue tumours was found to be higher in females (10/13, 76.92%) as compared to males (3/13, 23.08%) during this study (Table 2). Similarly, Hussain et al. (2020) [7] have made similar observations that the incidence of neoplasm was higher in females (55.36%) than males (44.64%). Roshini et al. (2013) [10] found an almost equal occurrence of canine tumours in male and female dogs, which may be due to a higher population of male dogs in a particular area. Hormonal interactions and gastrinreleasing peptide receptors are more common among female than male canines, which might be the reason for affecting a greater number of female cases than males in the present study. 3). Sostaric-Scase et al.

(2013) [12] recorded the highest incidence of tumours of skin and subcutis (45.73%), followed by mammary gland (21.75%) and genitalia (7.97%). Roshini et al. (2013) [10] recorded that mammary gland was the most preferred site for tumour development with the frequency of about 21.8%, followed by skin of leg region (20%), vagina and abdominal cavity (7.27%), testicle (5.45%), interdigital space (3.63%), gum (3.63%), perianal gland (3.63%), genital organs (3.63%), skin of chest region (3.63%). The least affected sites were ovary, vulva, eyelid, skull bone, ear canal, skin of mandible, rudimentary mammary gland, base of the tail, scrotal skin and skin of neck region, with 1.7% cases each. In this study, out of 13 cases, 7 cases of mammary gland tumours, four were histopathologically diagnosed as malignant, including adenocarcinoma (2 cases), tubular adenocarcinoma (1 case), and ductal carcinoma (1 case), while the remaining three cases were benign tumours, including adenochondroma (2 cases) and adenoma (1 case).

Lopuszynski and Hellmen (2015) [9] reported 66 cases of canine mammary gland tumours, with the most common benign tumours being adenoma, papilloma, and benign mixed tumour, while ductal and tubular carcinomas were the most common malignant types.

In this study, out of 13 cases, one case was found to be of epithelial origin, which was Squamous cell carcinoma. SCC is characterized by cords or nests of proliferating neoplastic cells, with immature polyhedral cells at the periphery and eosinophilic, lamellated keratin pearls at the centre. In welldifferentiated types, keratin production is abundant. The neoplastic cells display moderate pleomorphism, large vesicular nuclei, prominent nucleoli, variable mitotic activity, and distinct intercellular bridges (Chandrashekaraiah et al., 2011) [4] . Also, in this study, out of 13 cases, three were found to be of mesenchymal origin. Out of which, two cases were fibroma, and one case was hemangioma. Histopathological examination revealed bland, spindle-shaped cells embedded within a scant to moderately abundant fibrovascular stroma (Soltero-Rivera et al., 2015) [11] . While, hemangioma is a vascular tumour that arises within the collagen-rich dermis. They are unencapsulated but distinctly demarcated, often presenting as multilobular or coalescing masses. Histologically, they are composed of clusters of small blood vessels with concentric thickening formed by a few cellular layers (Warren et al., 2007) [13] . In this study, 2 cases of round cell tumours were also observed. Out of which, 1 case was lymphoma, and 1 case was plasmacytoma. Lymphoma is classified based on multiple morphological parameters, including growth pattern, nuclear size, nuclear features such as chromatin distribution and nucleolar number and positioning, mitotic activity, and immunophenotypic profile (Zandvliet, 2016) [15] . Plasmacytoma was consistent with a completely excised round-cell tumour, with Mott cell differentiation as the leading differential diagnosis. Electron microscopy revealed uniformly electron-dense intracytoplasmic granules with relatively smooth surfaces upon ultrastructural examination (Auch et al., 2024) [2] .

Conclusions

Canine soft tissue tumours were found more frequently in the age group of 9 to 12 years, with German Shephard was commonly affected breed; females are more prone to this type of tumour. The most common type of tumours in such breeds are mammary gland tumours. Surgical excision was considered a suitable technique for the management of benign tumours with short recovery time and without any major side-effects or complications. In the cases of malignant tumours, surgical management along with chemotherapy was found to be better, with the highest probability of cure, increased survival time and improved quality of life.

References

1. Arya SKD, Kumar K, Kumar D, Kumar S, Tiwary R, Sinha M, et al. Incidence of commonly occurring neoplasms amongst canines in Patna. Int J Curr Microbiol Appl Sci. 2018;7(5):2817-2823.
2. Auch CL, Michael A. Cutaneous plasmacytoma with Mott cell differentiation in a dog. J Vet Diagn Invest. 2024;36(4):564-568.
3. Bhimani H, Parikh PV, Barot HM, Mahla JK, Pankaj, Sodagar B. Epidemiology of canine mammary gland tumours. Int J Vet Sci Anim Husb. 2024;9(2):954-956.
4. Chandrashekaraiah GB, Rao S, Munivenkatappa BS, Mathur KY. Canine squamous cell carcinoma: a review of 17 cases. Braz J Vet Pathol. 2011;4(2):79-86.
5. Choi JW, Yoon HY, Jeong SW. Clinical outcomes of surgically managed spontaneous tumors in 114 client owned dogs. Immune Netw. 2016;16(2):116-125.
6. Da Silva EO, Di Santis GW, Headley SA, Bracarense APFRL. Pathological findings in the adrenal glands of 80 dogs. Acta Sci Vet. 2018;46:7-10.
7. Hussain SA, Prakashiny S, Noorunnisa N, Shree RR, Ganesh SN. Expression of human epidermal growth factor receptor 2/neu in breast carcinoma: experience from a tertiary care center in Tamil Nadu, India. Arch Med Health Sci. 2020;8(1):35-40.
8. Kitchell BE, Dervisis NG. Pathophysiology and tumor cell growth. In: Henry CJ, Higginbotham ML, editors. Cancer management in small animal practice. Maryland Heights, Missouri: Saunders, an imprint of Elsevier Inc.; 2010. p.1-3.
9. Lopuszynski W, Hellmen E. Cell proliferation study in canine mammary carcinomas. Int J Vet Health Sci Res. 2015;3(2):39-45.
10. Roshini S, Kadam DP, Moregaonkar SD, Sawale GK, Tripathi SD, Pawar AA, et al. Occurrence of different neoplasms of dogs in Mumbai region. Indian J Vet Pathol. 2013;37(2):138-140.
11. Soltero-Rivera M, Engiles JB, Reiter AM, Reetz J, Lewis JR, Sánchez MD. Benign and malignant proliferative fibro-osseous and osseous lesions of the oral cavity of dogs. Vet Pathol. 2015;52(5):894-902.
12. Sostaric-Scase IC, Severin M, Hohsteter B, Artukovic A, Beck A, Gudan Kurilj R. Incidence and types of canine tumours in Croatia. Veterinarski Arhiv. 2013;83(1):1-45.
13. Warren AL, Summers BA. Epithelioid variant of hemangioma and hemangiosarcoma in the dog, horse, and cow. Vet Pathol. 2007;44(1):15-24.
14. Witsch E, Sela M, Yarden Y. Roles for growth factors in cancer progression. Physiology. 2010;25(2):85-101.
15. Zandvliet M. Canine lymphoma: a review. Vet Q. 2016;36(2):76-104.