Adenosquamous carcinoma of the upper eyelid in a dog

Purpose: To describe an adenosquamous carcinoma of the upper eyelid in a dog. Methods: A 12-year-old, male mongrel dog with a 6-month history of a progressive eyelid mass of the right upper eyelid was evaluated. Long-term bilateral topical application of 0.03% tacrolimus for third eyelid plasmoma and treatment cycles with systemic corticosteroids for a long-standing atopic dermatitis were reported by medical history. Complete physical and ophthalmologic examination of the dog as well as CBC, serum biochemical analysis, urinalysis, thoracic radiographs, and abdominal ultrasonography were performed. The mass was surgically removed and the eyelid was restored using a semicircular rotational flap from the periocular region. The removed mass was routinely processed, and 4 µm-thick sections were stained with haematoxylin and eosin. An additional immunohistochemistry with the streptavidin-biotin peroxidase method, using an anti-pan cytokeratin antibody, was also performed. Results: Clinical staging did not show any abnormality. Histological examination showed an invasive proliferation of malignant epithelial cells with intermixing of both adenocarcinomatous and malignant squamous cell components. A diagnosis of eyelid adenosquamous carcinoma was made. No evidence of local recurrence or distance metastases was identified during the 12-month follow-up period. Conclusions: To the authors’ knowledge, this is the first report on an adenosquamous carcinoma of the eyelid in the dog. Immunosuppression was found to be a significant clinical risk factor for cutaneous adenosquamous carcinoma in humans and it was considered a possible risk factor in this dog.