title: Solitary plasmacytoma of bone in two successfully treated cats.
abstract: This is the first report of feline solitary plasmacytoma of bone. We describe the clinical, clinico-pathological, radiographic and pathological findings of two successfully treated cats with long-term follow-up. The first case presented with spinal pain and neurological deficits. Radiographs demonstrated sclerosis of lumbar vertebra L6 and a myelogram confirmed interference to flow of contrast in the L4-7 region. A biopsy of L6 revealed neoplastic plasma cell infiltration. There was no evidence of paraproteinaemia on serum protein electrophoresis. The cat underwent hypofractionated megavoltage radiotherapy. Clinical signs resolved completely and 4 years after diagnosis the cat remains well and has no electrophoretically detectable paraproteinaemia. The second case presented with neurological deficits of the tail and spinal radiographs revealed extensive osteolysis of the sacrum. A biopsy of sacral bone demonstrated neoplastic plasma cell infiltration. The animal was normoglobulinaemic. The cat improved clinically with induction chemotherapy (melphalan and methylprednisolone). The same chemotherapeutics were continued at maintenance doses for 4.3 years, at which time there was recurrence of neurological deficits and a palpable sacral mass. Cytological examination of a fine needle aspirate confirmed recurrence of plasma cell neoplasia. A low concentration monoclonal paraproteinaemia was detected. Vincristine was administered resulting in resolution of neurological deficits and a palpably smaller sacral mass. Eighteen months into vincristine therapy, there was recurrence of clinical signs and the cat was euthanased, more than 6 years after the initial diagnosis.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, UK. p.j.mellor.02@cantab.net <p.j.mellor.02@cantab.net>
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Mellor
authors.forename: Gerry A
authors.initials: GA
authors.lastname: Polton
authors.forename: Malcolm
authors.initials: M
authors.lastname: Brearley
authors.forename: Sean
authors.initials: S
authors.lastname: Haugland
authors.forename: Ken C
authors.initials: KC
authors.lastname: Smith
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Scase
authors.forename: Pauline E
authors.initials: PE
authors.lastname: McNeil
authors.forename: Andrew
authors.initials: A
authors.lastname: Holloway
authors.forename: Joy
authors.initials: J
authors.lastname: Archer
authors.forename: Roger M
authors.initials: RM
authors.lastname: Powell
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Villiers
authors.forename: Mike E
authors.initials: ME
authors.lastname: Herrtage
authors.forename: David J
authors.initials: DJ
authors.lastname: Argyle
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Day
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D002415:Cats; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D008297:Male; D010954:Plasmacytoma / Q000175:diagnosis / Q000628:therapy / Q000662:veterinary*; D011859:Radiography; D013125:Spinal Neoplasms / Q000175:diagnosis / Q000628:therapy / Q000662:veterinary*; D016896:Treatment Outcome