Differentiated embryonal rhabdomyosarcoma in a cow.

An embryonal rhabdomyosarcoma was found in the pleura of a 2-year-old Holstein cow after first delivery. The most predominant cells in the tumor were relatively small in size, but considerable numbers of more differentiated cells of larger sizes mingled with the small cells. The most differentiated cells were characterized by multinucleation, abundant cytoplasm containing cross-striated fibrils, intense immunoreactivity for desmin, and weak or negative reactivity for vimentin. Such cells, lacking mitotic activity and displaying weak or no reactivity for proliferating cell nuclear antigen, were considered to be malignant counterparts of myotubes or muscle fibers. This neoplasm seems to follow normal skeletal muscle embryogenesis, and to be capable of differentiation into the final stage of muscle development.     

Vaginal rhabdomyosarcoma in a dog

A 10-year-old, female, mongrel showed hemorrhage from vulva. By magnetic resonance image (MRI) and endoscopic examination, a multipapillary mass with a grape-like appearance was found around the urethral opening. Histologically, the mass consisted of variable-sized round-, spindle-to-polygonal-shaped tumor cells including many multinuclear cells. Mitotic figures were also frequently observed. In some areas, that tumor cells were loosely arranged, with intercellular myxoid components. Immunohistochemically, these tumor cells were strongly positive for vimentin and focally positive for desmin but negative for myoglobin. Thus, the case was diagnosed as a relatively poorly differentiated botryoid rhabdomyosarcoma by the macroscopic, histopathologic, and immunohistochemical identification. This is the first report of botryoid rhabdomyosarcoma developing in the vagina of a dog.     

Megaesophagus in a cow

Megaesophagus developed subsequent to presumed pharyngeal trauma in a cow. Signs resolved after prolonged antibiotic treatment and supportive care.     

Hemangiosarcoma in a cow

A 4-year-old cow initially examined because of hindlimb lameness had a waxing and waning course of illness for 31 weeks. Signs included lameness, swelling of the affected limb, and intermittent fever, and anorexia. Radiography and bacterial culturing suggested osteomyelitis. Terminally, there was peracute anemia and dyspnea. The final diagnosis was hemangiosarcoma of the metatarsus, with metastasis to the lungs.     

Intracardiac rhabdomyosarcoma in a dog

Intracardiac rhabdomyosarcoma was diagnosed in a 14-month-old Golden Retriever referred for evaluation of syncope. The dog was weak, with irregular heart rate, pulse deficit, heart murmur, and hepatomegaly. Thoracic radiography revealed generalized cardiomegaly, and electrocardiography revealed sinus rhythm with multiform ventricular premature complexes and intermittent ventricular tachycardia. Two-dimensional echocardiography revealed extensive soft-tissue density masses in both ventricles. An intracardiac neoplasm seen at postmortem examination was identified histologically as rhabdomyosarcoma, an uncommon intracardiac tumor in dogs.     

Auricular rhabdomyosarcoma in a rat

An ear (auricular) neoplasm from a 1-year-old male rat was removed surgically and examined histologically. Macroscopically, the neoplasm was firm, white and measured (0.5 x 0.5 cm). Microscopically, the neoplasm was expansile, non-encapsulated, and composed of large, pleomorphic, polygonal to spindle-shaped cells containing multiple nuclei. Using immunohistochemical and chemical stains, the neoplastic cells were positive for vimentin, myoglobin, phosphotungstic acid haematoxylin and desmin, but had no immunoreactivity for cytokeratin or alpha-smooth muscle actin. On the basis of histopathological, immunohistochemical and histochemical stains, a diagnosis of auricular rhabdomyosarcoma was made. Although reported infrequently in human, this is, to the author's knowledge, the first report that describes the detailed gross, histopathological, histochemical and immunohistochemical findings of auricular rhabdomyosarcoma in a rat.     

Perianal rhabdomyosarcoma in a dog

A perianal rhabdomyosarcoma was diagnosed in an 11-year-old neutered male Labrador retriever. Following two incomplete surgical excisions of the tumour, the dog was treated by means of surgery combined with local radiotherapy and systemic chemotherapy using one cycle of vincristine sulphate, doxorubicin and cyclophosphamide (VAC protocol). The dog died 252 days after the first combined therapy. Radiography at this time demonstrated enlargement of the iliac lymph nodes, suggesting metastasis of the tumour. To the authors' knowledge, this is the first report of treatment of canine perianal rhabdomyosarcoma.     

Endocarditis in a cow

Bacterial endocarditis of the tricuspid valve was diagnosed in a cow with weight loss, reduced milk production, and intermittent fever. Clinical signs of disease included jugular and mammary vein pulses, tachycardia, large cardiac silhouette, and grade-III/V holosystolic murmur. The diagnosis was also supported by echocardiographic findings and isolation of Streptococcus viridans from blood samples. The cow was treated with penicillin, furosemide, acetylsalicylic acid, heparin, and potassium chloride and survived 14 months after the diagnosis, producing 1 live calf and 4 viable embryos. The cow's heart rate exceeded an upper normal limit of 80 beats/min during most of the initial 4 months of treatment. Additional clinical signs of disease that were observed during treatment included diarrhea, ventral edema, and coughing. General medicine and cardiology textbooks have previously minimized the potential benefits of anticoagulant use in cases of septic endocarditis. The advent of routinely performed embryo transfer procedures may make treatment of endocarditis feasible in cattle with exceptional genetic merit.     

Bronchiolar adenocarcinoma in a cow

An aged beef cow had a primary lung tumor that was diagnosed postmortem. Clinical signs included inappetence, weight loss, coughing, dyspnea, and reduced lung sounds. Antibiotic treatment was ineffective. The cow was euthanatized. Postmortem examination revealed numerous, firm nodules throughout both lungs. Microscopically, the pulmonary nodules contained neoplastic cells and the diagnosis was bronchiolar adenocarcinoma. A diagnosis of pulmonary neoplasia, although rare, should be considered in an aged cow with similar historical and clinical findings.     

Aujeszky's disease in a cow

A non-suppurative encephalitis accompanied by intraneuronal intranuclear inclusions were observed in the brain from a cow that died within 10 hours of developing nervous signs. Immunogold-silver staining located Aujeszky's disease virus antigen in neuronal cytoplasm and the virus was isolated from large volumes of suspensions of nervous tissues and tonsils. Fattening pigs in adjacent buildings had high antibody titres to Aujeszky's disease virus. The methods by which the cow could have acquired infection are considered, and the significance of transient low titres of antibodies to Aujeszky's disease virus in in-contact cows is discussed.