Dermal squamous cell carcinoma (avian keratoacanthoma) in parakeets

Abstract

Tumor suspected operation materials obtained from eight parakeets are evaluated clinically, pathologically and immunohistochemically. The age of the parakeets varied from seven months to nine years old. Four were male, one was a female and the sexes of the rest three were not identified. Six of the operation materials were taken from the above the tail while the other two from beneath the wings. Evaluated tumors were observed to be hard in consistency and whitish color on cut surface. At histopathological examination; it is seen that hyperchromatic nucleated, big, ovoid shaped, pale eosinophilic cytoplasmated cells had formed groups in dermis. Keratinized horn pearl formations are identified in the centers of most of these cell groups. Within the horn pearl formations hyperkeratotic, parakeratotic changes and calcifications are found. In some cases inflammation areas consisting of heterophil leukocytes, lymphocytes and plasma cells in the dermis are observed. Also in histopathological examination of one case, tubercle formations made of coagulation necrosis in the center surrounded by heterophil leukocytes, macrophages, epithelioid cells, lymphocytes and foreign body giant cells are found as well as tumoral formations. Groups of cudgel shaped, red colored bacteria are found in Ziehl-Neelsen staining of the sections. Tissues are stained for proliferating cell nuclear antigen (PCNA) and p53 proteins immunohistochemically in order to interpret mitotic activity and malignancy of the tumor. TUNEL method is applied to the tissues to evaluate apoptosis.