title: Granulocytopenia associated with thymoma in a domestic shorthaired cat.
abstract: A 5-year-old, spayed female cat was referred because of a mass in the cranial mediastinum noted on thoracic radiographs. A thymoma was diagnosed following ultrasound and biopsy of the mass. Treatment was initiated with coarse-fraction radiation therapy using external-beam therapy (four fractions of 5 Gy). The mass responded, but granulocytopenia developed. Bone marrow examination showed a myeloid to erythroid ratio of approximately 1:1, with a left shift within the myeloid line. These findings, as well as the lack of toxic changes within the peripheral blood neutrophils, suggested immune-mediated destruction of peripheral granulocytes. Immune suppression with prednisone and cyclosporine was instituted. After 7 weeks, the neutrophil count returned to normal. The tumor was removed, and cyclosporine was reduced and eventually discontinued 3 weeks postsurgery.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington 99164-6610, USA.
authors.forename: Janean L
authors.initials: JL
authors.lastname: Fidel
authors.forename: Indira S
authors.initials: IS
authors.lastname: Pargass
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dark
authors.forename: Shannon P
authors.initials: SP
authors.lastname: Holmes
mesh_terms: D000380:Agranulocytosis / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000662:veterinary*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage; D002371:Cat Diseases / Q000175:diagnosis* / Q000628:therapy*; D002415:Cats; D016572:Cyclosporine / Q000008:administration & dosage; D005260:Female; D007153:Immunologic Deficiency Syndromes / Q000150:complications / Q000662:veterinary; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D009503:Neutropenia / Q000209:etiology / Q000662:veterinary; D011241:Prednisone / Q000008:administration & dosage; D011832:Radiation Injuries / Q000188:drug therapy / Q000662:veterinary; D011859:Radiography; D013945:Thymoma / Q000150:complications / Q000175:diagnosis / Q000628:therapy / Q000662:veterinary*; D013953:Thymus Neoplasms / Q000150:complications / Q000175:diagnosis / Q000628:therapy / Q000662:veterinary*; D016896:Treatment Outcome; D014861:Washington
chemical_list: D000893:Anti-Inflammatory Agents; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D011241:Prednisone