Pathological, histochemical, and immune-histochemical studies on some canine-skin neoplasm at Sharkia province, Egypt

Cutaneous neoplastic disorders are often observed in small mammal pets, such as dogs, regardless of their gender.

An important objective of this work was to give a full account of the clinical, pathological, and immune-histochemical features of several skin tumors in dogs.

This study was a case series in the hospital clinic, Faculty of Veterinary Medicine, Zagazig University, Egypt. Twenty-five dogs (14 males and 11 females) were examined clinically during the period from March 2022 to October 2023. The skin swelling was collected from affected animals and then subjected to a detailed histopathological study to record the different gross and microscopic findings and confirm the diagnosis by immunohistochemistry.

Skin neoplasia in dogs was exposed to various clinical signs, and the dogs' ages ranged between 3 and 11 years. Concerning tumor features, the majority of neoplasms were malignant (65.52%) more than benign (34.48%). The study revealed the presence of 29 cases of dogs showed neoplasia with different prevalence rates including squamous cell carcinoma (13.79%), mast cell tumor (6.89%), basal cell tumors (10.34%), histiocytoma (6.89%), trichoepithelioma (10.34%), transmissible venereal tumor (10.34%), trichilemmoma (3.44%), scalp paraganglioma (3.44%), pilomatricoma (10.34%), malignant melanomas (17.24%), and miscellaneous cases as fat necrosis (6.89%), in males and females dogs with different histopathological lesions and immunohistochemistry expressions for pan-cytokeratin (CK), melanocyte-differentiation antigens (S100 protein), and synaptophysin.

Malignant melanomas (17.24%) are the extremely common cutaneous tumors diagnosed in this study. Meanwhile, benign tumors such as trichilemmoma, trichoepithelioma, pilomatricoma, and paraganglioma are less frequent in dogs.