title: Rhabdomyosarcoma associated with the lead wire of a pacemaker generator implant.
abstract: An 11-year-old female spayed Labrador Retriever was presented for a draining, painful subcutaneous mass palpated over a previously implanted pacemaker generator. Infection was suspected and the mass was removed surgically. On cut surface, the mass was friable and mottled tan to brown with firm pale tan nodules, surrounding the pacemaker lead wire adjacent to the pacemaker generator. Cytologic interpretation of impression smears was consistent with a sarcoma, and suggestive of a rhabdomyosarcoma due to the presence of strap-like cells. On histopathologic examination, a highly invasive nodular mass surrounded the pacemaker lead, composed of pleomorphic round, spindle and strap cells, and multinucleated giant cells. The population exhibited microscopic invasion into the deep portion of the fibrous capsule surrounding the pacemaker generator. There were tumor emboli within small to medium subcutaneous veins adjacent to the mass. Immunohistochemically, the neoplastic cells stained positive for α-sarcomeric actin and vimentin, and negative for α-smooth muscle actin, consistent with a rhabdomyosarcoma arising at the site of the pacemaker generator. To our knowledge, this is the first report of a rhabdomyosarcoma associated with the lead wire of a pacemaker generator in a dog.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.
authors.forename: Kelley M
authors.initials: KM
authors.lastname: Thieman Mankin
authors.forename: Mark D
authors.initials: MD
authors.lastname: Dunbar
authors.forename: David
authors.initials: D
authors.lastname: Toplon
authors.forename: Pamela
authors.initials: P
authors.lastname: Ginn
authors.forename: Herbert W
authors.initials: HW
authors.lastname: Maisenbacher
authors.forename: Marije
authors.initials: M
authors.lastname: Risselada
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000209:etiology / Q000473:pathology*; D004285:Dogs; D005260:Female; D005549:Foreign-Body Reaction / Q000209:etiology / Q000662:veterinary*; D007854:Lead; D010138:Pacemaker, Artificial / Q000009:adverse effects / Q000662:veterinary*; D019736:Prostheses and Implants / Q000009:adverse effects / Q000662:veterinary*; D012208:Rhabdomyosarcoma / Q000209:etiology / Q000473:pathology / Q000662:veterinary*
chemical_list: D014408:Biomarkers, Tumor; D007854:Lead
keywords: Carcinogenesis; foreign body; implant; neoplasia; pacemaker; sarcoma