Tibiotarsal Subcutaneous Xanthogranuloma in a Rose-breasted Cockatoo (Eolophus roseicapilla): A Case Report

Background: Xanthogranuloma (xanthoma) presents as a rare, non-infectious granulomatous lesion with a yellowish and soft appearance. Hypercholesterolemia and hyperlipidemia are believed to be the underlying causes of this lesion. Xanthoma has been identified in vertebrates and humans.  Objectives: This report presents a case of cutaneous xanthogranuloma located in the tibiotarsal region of a 5-year-old rose-breasted cockatoo (Eolophus roseicapilla) fed with high-fat diets. Methods: The cockatoo underwent anesthesia using isoflurane administered through a face mask connected to an Ohmeda anesthesia machine. The mass was surgically removed and submitted for histopathological examination. The tissue was fixed in 10% neutral buffered formalin, and representative sections were routinely processed for hematoxylin and eosin (H E) staining. Moreover, frozen sections were obtained and stained with the Oil Red O technique. Results: Upon histopathologic examination of routine H E slides, vacuolated macrophages, and multinucleated giant cells were noted in addition to cholesterol clefts and heterophilic infiltrates. Oil Red O staining was performed to detect intracellular and extracellular lipid content. Xanthogranulomas invaded the surrounding tissues, necessitating complete surgical excision. The lesion did not recur during the 1-month follow-up, but the patient died due to respiratory disorders.  Conclusion: Stress and high-lipid feed consumption were considered the predisposing factors to xanthogranuloma development in this bird.