title: Neoplastic pleural effusion and intrathoracic metastasis of a scapular osteosarcoma in a dog: a multidisciplinary integrated diagnostic approach.
abstract: A 10-year-old, female spayed mixed-breed or cross-bred dog was referred to the Small Animal Teaching Hospital of the University of Liverpool due to tachypnea, dyspnea, and pleural effusion not responding to diuretics and antibiotics. The chest was drained and cytology of the pleural fluid was consistent with a modified transudate with presence of atypical cells initially attributed to mesothelial hyperplasia and dysplasia. Computed tomography detected, in addition to the bilateral pleural effusion, diffuse pleural thickening, multiple pleural and pulmonary nodules, and a mineralized and lytic mass in the left scapula. Imaging findings were suggestive of a primary bone tumor with intrathoracic metastasis. Cytology of the left scapular and pleural masses revealed a malignant neoplasm highly suggestive of osteosarcoma. The diagnosis was confirmed by demonstration of a positive cytochemical reaction for alkaline phosphatase on prestained cytology slides. This finding prompted review of the initial interpretation of the pleural effusion cytology. The presence of neoplastic osteoblasts in the thoracic fluid was identified by a combination of cytochemistry, cell pellet immunohistochemistry, and transmission electron microscopy findings. In this report, a multidisciplinary integrated diagnostic approach was used to diagnose and confirm a neoplastic pleural effusion due to osteosarcoma metastasis in a dog.
authors.affiliation: Department of Small Animal Clinical Science, Institute of Veterinary Science, University of Liverpool, Neston, UK.
authors.forename: Luis
authors.initials: L
authors.lastname: Mesquita
authors.affiliation: Department of Small Animal Clinical Science, Institute of Veterinary Science, University of Liverpool, Neston, UK.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Mortier
authors.affiliation: Department of Veterinary Pathology and Public Health, Institute of Veterinary Science, University of Liverpool, Neston, UK.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Ressel
authors.affiliation: Department of Small Animal Clinical Science, Institute of Veterinary Science, University of Liverpool, Neston, UK.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Finotello
authors.affiliation: Department of Small Animal Clinical Science, Institute of Veterinary Science, University of Liverpool, Neston, UK.
authors.forename: Paolo
authors.initials: P
authors.lastname: Silvestrini
authors.affiliation: Department of Small Animal Clinical Science, Institute of Veterinary Science, University of Liverpool, Neston, UK.
authors.forename: Martina
authors.initials: M
authors.lastname: Piviani
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D002371:Cat Diseases / Q000175:diagnosis* / Q000473:pathology; D002415:Cats; D004285:Dogs; D005260:Female; D012516:Osteosarcoma / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D016066:Pleural Effusion, Malignant / Q000175:diagnosis / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D012540:Scapula / Q000473:pathology; D013899:Thoracic Neoplasms / Q000556:secondary / Q000662:veterinary; D014057:Tomography, X-Ray Computed / Q000662:veterinary
keywords: Bone tumor; cell pellet immunohistochemistry; computed tomography; dog; fluid cytology; transmission electron microscopy