What is your diagnosis?History
A 6-year-old blue-and-gold macaw (Ara ararauna), of unknown sex, was presented to the Louisiana State University Veterinary Teaching Hospital (Baton Rouge, LA, USA) for recurrence of a mass on the right eye. The bird was part of a private collection of more than 20 psittacine birds. The macaw was captive-bred and hand-reared by the owner and kept in the same room with the other birds. The diet consisted primarily of a seed mixture, with daily offerings of fresh fruits and vegetables (apples, strawberries, broccoli, corn). The flock had no history of major health problems.
Four weeks before the current presentation, the bird had been examined because of a mass on the right eye that was diagnosed as a squamous cell carcinoma of the third eyelid. The third eyelid mass was removed en bloc with complete surgical margins achieved as confirmed by histopathologic examination. Fluorescein staining demonstrated no corneal ulcers, and the bird was discharged with flurbiprofen (1 drop OD q12h for 10 days; Ocufen, Allergan Inc, Irvine, CA, USA) and neomycin/polymyxin B (1 drop OD q12h for 10 days). Recommendations for a conversion to a pelleted diet were also provided.
On the second presentation, the bird was bright, alert, and responsive, weighed 1.37 kg, and had a body condition score of 5/5. The owner had observed a mass on the right eye that had drastically increased in size during the past 5 days and was now irritating the bird. Occasional sneezing was also reported. Because of the fractious nature of the bird, it was sedated with midazolam administered intranasally (0.6 mg/kg) for an ophthalmic examination and venipuncture.
The examination revealed epiphora, blepharospasm, and mild conjunctivitis. A mass approximately 5 mm in diameter was observed originating from the palpebral surface of the lower right eyelid (Fig 1). Results of a baseline complete blood cell count and plasma biochemical analysis were unremarkable. The bird was anesthetized with isoflurane, and the mass was removed en bloc.
At surgical resection, the mass grossly appeared to infiltrate the third eyelid with some involvement of the sclera. Anesthetic recovery for the macaw was unremarkable.
[FIGURE 1 OMITTED]
[FIGURE 2 OMITTED]
On histopathologic examination, the mass consisted of diffuse, reactive fibroplasia and moderate, granulomatous inflammation (Figs 2 and 3). No evidence of an infectious or neoplastic etiology was present.
Resolutions of clinical signs were achieved during hospitalization. Medications dispensed at discharge were flurbiprofen and neomycin/polymyxin B, following the same regime as at initial presentation.
The differential diagnoses for the recurrent mass included neoplasia (squamous cell carcinoma, adenocarcinoma, papilloma), and infectious (bacterial, fungal) and noninfectious granuloma. Ocular neoplasia in birds has been reported infrequently, and solitary tumors of the nictitating membrane even less so. (1) The incidence of squamous cell carcinoma in birds is very low, (2-6) and, to our knowledge, only a single case of squamous cell carcinoma on the third eyelid has been reported. (1) Lesions in domestic species, including canids and bovids, tend to be locally invasive and carry a poor prognosis. (4.7) Adjunctive therapies available for local tumor control include photodynamic therapy (PDT), radiation therapy, and strontium-90.
Photodynamic therapy involves free-radical oxygen release when a photosensitizing compound is administered systemically and activated by a light of a specific wavelength. Suedmeyer et al (3) reported PDT of a squamous cell carcinoma on the propatagium of an African ring-nosed parakeet (Psittacula krameri), leading to an initial reduction in tumor burden. However, despite 5 treatments, remission was not achieved. An earlier attempt with PDT on a great hornbill (Buceros bicornis), (8) also with squamous cell carcinoma, described a transient limb paralysis, which was attributed to an ischemic or thromboembolic event because of vasoconstrictive effects of PDT.
[FIGURE 3 OMITTED]
Epithelial-based tumors are moderately responsive to radiation therapy and, in conjunction with insufficient dosing and inadequate surgical debulking, treatment failure transpires. (9) The use of cobalt radiation therapy after surgical resection of a cutaneous squamous cell carcinoma in an American flamingo (Phoenicopterus ruber) was unsuccessful in achieving remission. (2) Furthermore, recurrence was observed on the contralateral limb.
Common metastatic routes of neoplastic cells are local invasion and lymphatic, hematogenous, and peritoneal dissemination, (10) Perineural invasion is an under-recognized route of metastatic spread, where neoplastic cells spread by local peripheral nerves. The poor prognosis is because neoplastic cells are hidden from surgical resection leading to recurrence. (2,11) In this blue-and-gold macaw, this type of spread cannot be ruled out and can only be confirmed by enucleative histopathology.
Our primary differential on the second presentation was a recurrence of the squamous cell carcinoma previously resected from the same area. The histopathologic finding of the second mass was encouraging and provided the bird with a better prognosis. We speculate that the second mass originated because of aggressive healing and inflammation at the prior surgical site. As of the writing of this article, 1 year later, the bird was doing well, and there was no evidence of recurrence at the surgical site. Although squamous cell carcinoma usually carries a poor prognosis, we believe that this bird has a good prognosis for long-term survival.
This case was submitted by Kim Le, BSc, BVSC, Sydney, Australia, and Javier Nevarez, DVM, Phi), Dipl ACZM, Louisiana State University School of Veterinary Medicine, Department of Veterinary Clinical Sciences, Baton Rouge, LA 70803, USA (Nevarez). Present address (Le): Sydney, Australia.
(1.) Kern T J, Paul-Murphy J, Murphy C J, et al. Disorders of the third eyelid in birds: 17 cases. J Avian Med Surg. 1996;10(1):12-18.
(2.) Abu J, Wunschmann A, Redig PT, Feeney D. Management of a cutaneous squamous cell carcinoma in an American flamingo (Phoenicopterus ruber). J Avian Med Surg. 2009;23(1):44-48.
(3.) Suedmeyer WK, Henry C, McCaw D, Boucher M. Attempted photodynamic therapy against patagial squamous cell carcinoma in an African rose-ringed parakeet (Psittacula krameri). J Zoo Wildl Med. 2007;38(4):597-600.
(4.) Diaz-Figueroa O, Tully TN Jr, Williams J, Evans D. Squamous cell carcinoma of the infraorbital sinus with fungal tracheitis and ingluvitis in an adult Solomon eclectus parrot (Eclectus roratus solomonensis). J Avian Med Surg. 2006;20(2): 113-119.
(5.) Malka S, Keirstead ND, Gancz AY, et al. Ingluvial squamous cell carcinoma in a geriatric cockatiel (Nymphicus hollandicus). J Avian Med Surg. 2005; 19(3):234-239.
(6.) Manucy TK, Bennett RA, Greenacre CB, et al. Squamous cell carcinoma of the mandibular beak in a Buffon's macaw (Ara ambigua). J Avian Med Surg. 1998;12(3):158-166.
(7.) Lawrie A. Systemic non-infectious disease. In: Harcourt-Brown N, Chitty J, eds. BSAVA Manual of Psittacine Birds. Gloucester, England: British Small Animal Veterinary Association; 2005:262-265.
(8.) Suedmeyer WK, McCaw D, Turnquist S. Attempted photodynamic therapy of squamous cell carcinoma in the casque of a great hornbill (Buceros bicornis). J Avian Med Surg. 2001;15(1):44-49.
(9.) Filippich LJ. Tumor control in birds. Semin Avian Exot Pet Med. 2004; 13(1):25-43.
(10.) Marchesi F, Piemonti L, Mantovani A, Allavena P. Molecular mechanisms of perineural invasion, a forgotten pathway of dissemination and metastasis. Cytokine Growth Factor Rev. 2010;21(1): 77-82.
(11.) Liebig C, Ayala G, Wilks JA, et al. Perineural invasion in cancer: a review of the literature. Cancer. 2009; 115(15):3379-3391.