title: Giant cell tumour of bone in a cat with extraskeletal metastases: pathological and immunohistochemical study.
abstract: A case of giant cell tumour of bone (GCTb) in the lung and in a subcutaneous mass located in the right flank, with a probable primary origin in the mid-diaphysis of the right tibia, was described in a 8-year-old female cat. Numerous multinucleated giant cells were homogeneously distributed among a population of ovoid or spindle-shaped mononuclear cells. All of them were positive for vimentin suggesting a mesenchymal origin. Spindle-shaped tumour cells resemble fibroblastic cells, showing collagen fibres in their vicinity. Ovoid mononuclear cells are similar to macrophages, with a cytoplasm rich in electron-dense lysosomes. Multinucleated giant cells appear morphologically similar to osteoclasts. These findings are supported for the positive reaction to tartrate-resistant acid phosphatase (TRAP) and lysozyme, encountered only in ovoid and multinucleated giant cells. No immunoreactivity against human oestrogen receptors was observed in the nuclei of any neoplastic cells.
authors.affiliation: Dpto. Patología Animal: Medicina Animal (Anatomía Patológica), Facultad de Veterinaria, Universidad de León, Campus de Vegazana, s/n, 24071 León, Spain. dmamfe@unileon.es
authors.forename: M C
authors.initials: MC
authors.lastname: Ferreras
authors.forename: M
authors.initials: M
authors.lastname: Fuertes
authors.forename: V
authors.initials: V
authors.lastname: Pérez
authors.forename: J
authors.initials: J
authors.lastname: Benavides
authors.forename: C
authors.initials: C
authors.lastname: García-Pariente
authors.forename: L E
authors.initials: LE
authors.lastname: Reyes
authors.forename: J F
authors.initials: JF
authors.lastname: García-Marín
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D002371:Cat Diseases / Q000175:diagnosis* / Q000473:pathology; D002415:Cats; D003937:Diagnosis, Differential; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000175:diagnosis / Q000556:secondary / Q000662:veterinary*; D007150:Immunohistochemistry / Q000662:veterinary; D008175:Lung Neoplasms / Q000175:diagnosis / Q000556:secondary / Q000662:veterinary; D009362:Neoplasm Metastasis; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000556:secondary / Q000662:veterinary