Uropygial Gland Inflammation, Neoplasia and Surgical Resection in Six Northern Carmine Bee-Eaters (Merops nubicus nubicus)
A male northern carmine bee-eater (Merops nubicus nubicus), wild caught in Senegal in 1992, developed a large, crusty, ulcerated mass adhered to and protruding from the area of the uropygial gland. The mass was surgically removed and was histologically identified as a carcinoma with squamous and sebaceous differentiation. The bird was euthanatized 10 days post surgery due to deteriorating condition, and on necropsy, neoplastic cells had invaded the vertebral bodies. Evaluation of the remaining 10 bee-eaters in the flock (all wild-caught before 1993) revealed two male and two female birds with similar uropygial gland lesions. Following surgical excision of the masses, these four bee-eaters recovered from surgery without complication. Biopsies revealed squamous metaplasia and chronic active adenitis in all four glands, and carcinoma in three glands. Immunohistochemical staining for papillomavirus was performed on one bee-eater biopsy and was negative. Serum vitamin A levels ranged 1.98–3.24 ppm (mean 2.68 ppm) and were similar to values in unaffected bee-eaters, making hypovitaminosis A unlikely. Of the four bee-eaters that survived the immediate 3 weeks postoperative period, one bee-eater developed a recurrence of the uropygial mass at 185 days post surgery. The remaining three bee-eaters are still disease-free at 673–700 days post surgery. In addition, a new lesion was discovered in a previously unaffected bee-eater 689 days after the initial evaluation of the entire flock. While a definitive etiology was not identified, the lesions may be associated with increasing age. A close evaluation of the uropygial gland should be included in any avian physical examination.