Estágio na secção de Anatomia Patológica da Faculdade de Veterinária - UEM - achados clínicos, radiológicos e patológicos de osteossarcoma apendicular em dois gatos sem raça definida

Abstract

This report describes the activities carried out during the internship at the Pathological Anatomy Section of the Faculty of Veterinary Medicine at Eduardo Mondlane University, from April to August 2025. During this period, 84 animals of the following species were received: forty-one (41) dogs (49%); thirty-seven (37) chickens (44%); and two (2) of the following species: rabbits (2%); cats (2%); sheep (2%). Cytological (5%), histopathological (9%) and necroscopic (84%) examinations were performed. The most observed neoplasms in dogs (the most represented species) were those of the integumentary system, namely: mast cell tumor (2), squamous cell carcinoma (2) and melanoma (2). Among all the neoplasms diagnosed during the internship, appendicular osteosarcoma in cats was selected due to the rarity of bone neoplasms. Therefore, the objective of this report is to describe the clinical, radiological, and pathological findings of appendicular osteosarcoma in two mixed-breed cats admitted to the Veterinary Teaching Hospital, designated cat 1 (P1) and cat 2 (P2). Both were mixed-breed, intact males, 8 and 16 years old, respectively. The complaints presented by the owners were: apathy, progressive weight loss, swelling at the affected site, lameness, and P1: a wound that did not heal. For the diagnosis, the following examinations were performed: general physical, specific, radiographic, and histopathological. On general physical examination (nutritional status, mucous membranes, lymph nodes, heart rate, respiratory rate, and body temperature), the following was observed: P1: poor nutritional status, pale mucous membranes; P2: good nutritional status, pink mucous membranes, hydrated, asymmetry of thoracic limbs, respiratory difficulties (dyspnea), non-reactive lymph nodes (both patients). The specific examination of the thoracic limbs (lameness, limb symmetry, size and consistency of the swelling, signs of pain) revealed firm nodules in the following regions: P1: radio-ulna, 50x40x30mm in length, surface covered by skin, partially hairless; P2: swelling along the entire length of the humerus. Radiographic examination of the limbs showed: P1: bone destruction (radius-ulna) and P2: radiolucency (humerus). The prognosis was considered: P1: guarded and P2: poor. Due to the poor clinical condition of the patients and at the request of the owners, the cats were euthanized and the carcasses sent to SAP for histopathological examination. During the necropsy, macroscopic examination of the cadavers revealed whitish neoplastic nodules (P1 and P2). The neoplastic mass in the proximal humerus P2: measured 80x70x60mm, infiltrating the long head and lateral head of the triceps brachii muscles. And in the lung parenchyma, whitish nodular formations were observed, diffusely distributed and of different sizes (1-4mm) (suggestive of metastases). Samples of the neoplastic nodules from the thoracic limbs and lung of P2: were stained with Hematoxylin-Eosin. Based on the histopathological characteristics, the diagnosis of appendicular osteosarcoma and its respective subtypes were confirmed, being: P1: Giant cell appendicular osteosarcoma, grade II and P2: Productive osteoblastic appendicular osteosarcoma, grade III with lung metastases(TRADUÇÃO NOSSA)