一只5岁的雄性非洲灰鹦鹉（Psittacus erithacus）出现了多个生长缓慢、坚固的双侧贯穿眼眶背侧的肿块。通过计算机断层扫描成像，发现头部前背侧存在轻微、不完全的桥接骨形成。在左眶前背部位骨形成量适中，并有轻微的软组织肿胀。从肿块中进行手术活检，并对最顶部右侧的肿块进行组织病理学分析，结果显示出被致密纤维结缔组织包围的良性分化骨；骨内散布着良性分化骨细胞，未发现肿瘤变化或感染因素。组织病理学变化与异位成骨的发生一致。通过饲主的历史调查得知鹦鹉曾遭头部创伤，很可能导致该非洲灰鹦鹉的颅内异位成骨。

A 5-year-old, male African grey parrot (Psittacus erithacus) was presented with multiple, slow-growing, firm, bilateral masses around the dorsal orbital rims. Computer tomographic imaging revealed mild, incomplete bridging bone formation on the rostrodorsal aspects of the head. A moderate amount of smooth bone formation was identified at the rostrodorsal aspect to the left orbit, with minimal associated soft tissue swelling. Surgical biopsies were collected from the masses and histopathological analysis of the most rostral right mass showed well-differentiated bone, surrounded by dense fibrous connective tissue. Scattered, well-differentiated osteocytes were present within the bone. No evidence of neoplastic changes or infectious agents were identified. The histopathological changes were consistent with metaplastic bone formation. History obtained from the owner revealed recent head trauma, which likely induced the cranial heterotopic ossification in the African grey parrot.