Tumor maligno da bainha de nervo periférico e osteopatia hipertrófica em cadela / Malignant peripheral nerve sheath tumor and hypertrophic osteopathy in a bitch

ABSTRACT

Background: Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive, relapsing, metastatic cutaneousneoplasms of mesenchymal origin. So far, no account on the association of this disease with hypertrophic osteopathy (HO)in dogs is available in the literature. Current theories on the possible causes of HO suggest that this disease may be triggered by a primary neoplasm as well as by its metastasis. The objective of this work is to report the clinical, cytological,radiographic, histopathological, and immunohistochemical aspects of a dog affected by MPNST and HO.Case A 13-year-old female mongrel dog was presented with a history of ulcerated nodular lesion on the skin of the flank.Several ulcerated and non-ulcerated tumors were observed on the thorax, neck, and head at the physical exam. Cytological examination of the nodules revealed presence of mesenchymal cells with a malignant aspect. Complete blood countrevealed anemia. There were no alterations in the biochemical tests performed. Thoracic radiographs showed presence of anodular interstitial pattern in the cranial, medial, and caudal lobes of the lungs. To improve quality of life of the patient, theveterinary team opted for surgical excision of the tumoral ulcerations. Slight claudication in the pelvic limbs was noticedprior to the surgery. Histopathological analyses of the excised nodules verified the existence of malignant mesenchymalneoplasia, which was categorized as peripheral nerve sheath tumor after immunohistochemical examination. Additionalcutaneous tumors emerged after surgical excision, along with increased claudication, edema, and pain in the legs. Completeblood count revealed persistent anemia, lymphopenia, monocytosis, and neutrophilia. Radiographs showed an increasein the number and size of the nodules. Radiography of the limbs showed presence of palisading periosteal reaction, andincreased...