Osteocondromatose em agapornis (Agapornis fischeri): revisão de literatura e relato de caso

Abstract

Osteochondromatosis is a benign bone neoplasm that manifests through the development of multiple osteochondromas, primarily affecting bones that develop by endochondral ossification, such as long bones. Involvement of bones that undergo intramembranous ossification is rare. In domestic animals, there is no racial or sexual predisposition, and the etiopathogenesis of this condition remains unknown. Although osteochondromatosis has been described in various species, including humans, horses, dogs, rodents, and felines, reports of the disease in birds are rare. To our knowledge, this is the first report of osteochondromatosis in birds involving bones formed not only by endochondral ossification but also by intramembranous ossification. The aim of this study was to review osteochondromatosis, its clinical, epidemiological, and pathological aspects, and to report a rare case in a lovebird (Agapornis fischeri) involving both endochondral and intramembranous ossification bones. A female lovebird, approximately three years old, was referred to the Pathology Department of the Veterinary School at the Federal University of Minas Gerais for necropsy. The bird had a history of apathy, respiratory and feeding difficulties, and an inability to fly. Macroscopically, expansive multinodular enlargements of varying sizes and degrees of hardness were observed in the sternum, skull, right radiocarpal joint, ulna, humerus, ribs, and vertebrae. Post-mortem radiographic examination revealed nodules with varying degrees of radiopacity. Microscopically, the neoplastic nodules were almost always located on the cortical surface of the affected bones and were composed of a layer of chondrocytes in different stages of differentiation, predominantly hypertrophic and well differentiated. Adjacent to the neoplastic cartilaginous tissue, osteoid matrix or mature, mineralized trabecular bone tissue, formed by endochondral ossification, was observed. Hematopoietic tissue and adipose tissue were observed among the trabecular bone within the neoplasm. Based on radiographic, macroscopic, and microscopic characteristics, a diagnosis of osteochondromatosis was made. Despite being a rare neoplasm in birds, osteochondroma should be included in the differential diagnosis of primary bone neoplasms, especially in captive birds.