Low-grade adenocarcinoma of the palpebral conjunctiva\third eyelid in a pigeon (Columba livia): A case report

Adenocarcinomas involving ocular structures in birds are exceptionally rare and scarcely documented in the literature. This report details the first documented case of a low-grade adenocarcinoma originating from the palpebral conjunctiva and third eyelid in a Columba livia (pigeon). An adult pigeon was referred for specialized veterinary evaluation due to a progressively enlarging, slow-growing mass located in the periocular region of the left eye. Clinically, the tumor presented as a bilobed, pendulous mass with a soft consistency and a reddish, verrucous surface. The lesion appeared moist, with fluid exudation resulting in feather matting on the face and neck. Surgical excision of the mass was performed, and the tissue was preserved in 10% neutral-buffered formalin for histopathological evaluation. Preoperative fasting lasted at least three hours. The pre-anesthetic protocol included intramuscular Meloxicam 0.2% at 0.07 mg/kg, administered using a 26G insulin syringe. Anesthesia induction used isoflurane gas via mask at 3%–5%, then maintained at 1.5%–3.0%. After reaching adequate anesthetic depth, the mask was removed, and the patient was intubated with a size 2 cuffless endotracheal tube. The pigeon was positioned in dorsal recumbency, wrapped in aluminum foil, and placed on a USB-powered heating pad. A pulse oximeter monitored oxygen saturation on the left pelvic limb. The surgical site was aseptically prepared with iodinated alcohol. Lidocaine was infiltrated locally before incision. The tumor was excised with a scalpel following hemostatic clamping, and safety sutures were placed using nylon 5.0 thread. Intraoperatively, 4 mL of warmed lactated Ringer’s solution was administered subcutaneously, alongside enrofloxacin 2.5% (0.28 mL), dexamethasone (0.2 mL), and vitamin K (0.2 mL). Histopathology confirmed a low-grade adenocarcinoma of the palpebral conjunctiva/third eyelid.