Comprehensive evaluation of auricular squamous cell carcinoma in dogs: Clinical and pathological perspectives

Abstract

Squamous cell carcinoma (SCC) is one of the most frequently encountered malignant cutaneous neoplasms in dogs particularly affecting sun-exposed regions such as the pinna. The present study was conducted over a period of one year to evaluate the
prevalence, haematological, biochemical and histopathological characteristics of auricular SCC in 786 dogs of different breeds
of canine dermatological cases presented to the Teaching Veterinary Clinical Complex, Bihar Veterinary College, BASU, Patna.
Twenty-two cases were recorded having squamous cell carcinoma with a mean age of 9.1 ± 2.3 years. The overall prevalence rate
of auricular SCC during the study period was 2.8% among canine dermatological cases. Breed-wise prevalence indicated higher
incidence in German Shepherds (32%), Labrador Retrievers (27%), Spitz (18%) and non-descript dogs (23%) with a higher occurrence
in males. Clinically, affected dogs exhibited ulcerated, proliferative or crusted growths on the pinna, foul-smelling discharge, head
shaking, pain and pruritus in chronic cases. Haematological analysis revealed moderate anaemia, leucocytosis and neutrophilia
indicative of chronic inflammatory response and tumour-associated infection. Biochemical evaluation demonstrated elevated
liver enzymes (ALT, AST) and increased total protein and globulin levels suggestive of systemic inflammatory and hepatic stress
responses. Histopathological examination confirmed the diagnosis revealing invasive nests and cords of neoplastic squamous
epithelial cells with keratin pearl formation, cellular pleomorphism, mitotic figures and stromal desmoplasia consistent with well
to moderately differentiated SCC. Auricular squamous cell carcinoma in dogs is a relatively common malignant neoplasm with
breed predisposition and distinct clinico-pathological alterations. This study highlights the clinicopathological significance of
auricular squamous cell carcinoma in dogs emphasizing the importance of early diagnosis, surgical management and awareness
among veterinarians and dog owners particularly in predisposed breeds such as German Shepherds and Labradors exposed to
prolonged sunlight. Early recognition through clinical and histopathological correlation is crucial for timely management and
to prevent local invasiveness and recurrence.