History
An 11-year-old 9.9-kg (21.8-lb) neutered male Beagle was evaluated because of a mass in the left ventral cervical region. The mass had been present for approximately 6 months and had recently increased in size. Prior fine-needle aspiration yielded only hemorrhage. Results of recent 3-view thoracic radiography, a CBC, a whole blood biochemical profile, and assessment of whole blood total thyroxine concentration were unremarkable apart from mild thrombocytopenia (112 × 103 platelets/μL; reference range, 170 × 103 platelets/μL to 400 × 103 platelets/μL).
Clinical and Gross Findings
On physical examination, the dog was alert, ambulatory, and mildly tachypneic with pale mucous membranes. The cervical mass measured 5 × 5 × 3 cm, was soft, and was fixed to underlying soft tissue. Diagnostic testing revealed anemia (PCV, 20%; reference range, 36% to 60%) and thrombocytopenia (51 × 103 platelets/μL) with normal prothrombin time and activated partial thromboplastin time. Pleural effusion was diagnosed, and thoracocentesis yielded hemorrhagic fluid (PCV, 45%).
Computed tomography of the dog's head and neck revealed a soft tissue-attenuating mass that extended from the thyroid gland to just cranial to the manubrium. The mass had effaced the left external jugular vein and appeared to invade the cervical musculature. Two soft tissue-attenuating nodules were identified in the right cranial lung lobe. A nodule in the cranial aspect of the liver was also seen. Moderate pleural and mild mediastinal effusion were present. Owing to the dog's clinical findings and deteriorating quality of life, the client elected euthanasia several days later. Following euthanasia, the dog was submitted for necropsy.
At necropsy, findings included extensive subcutaneous and intermuscular hemorrhage surrounding the mass. The mass was ill defined and multifocally cavitated with blood-filled spaces (Figure 1). The mass blended with the surrounding muscles and was wrapped around the left jugular vein, which was irregularly dilated and thin. A scant amount of thin, red-tinged fluid was present upon opening the thorax. The lungs were diffusely mottled, and dozens of 0.1- to 0.2-cm-diameter raised, red foci were randomly distributed throughout the parenchyma. The liver had multiple flat, dark red areas that ranged from 0.1 to 0.3 cm in diameter and were randomly distributed throughout all lobes. All remaining organs were grossly unremarkable.
Photographs of an 11-year-old Beagle that developed a mass in the left ventral cervical region. The mass is grossly visible, 5 × 5 × 3 cm, soft, and fixed to underlying soft tissue (A). Surrounding the mass, there is subcutaneous and intermuscular hemorrhage (B and C), and the mass is cavitated with blood-filled spaces (D).
Citation: Journal of the American Veterinary Medical Association 255, 9; 10.2460/javma.255.9.1019
Formulate differential diagnoses from the history, clinical findings, and Figure 1—then turn the page→
Histopathologic Findings
Arising from and expanding the wall of the jugular vein was an unencapsulated, poorly demarcated, moderately cellular, infiltrative mass composed of spindle-shaped cells that formed irregularly sized blood-filled vascular channels (Figure 2). Cells of the mass had variably distinct borders, a moderate amount of eosinophilic fibrillar cytoplasm, and an irregularly oval to elongate nucleus that occasionally bulged into vascular channels and had coarsely clumped chromatin and 1 or 2 distinct nucleoli. There were 2 to 4 mitotic figures/hpf (40×; Figure 3). Anisokaryosis and anisocytosis were marked. Adjacent myocytes were degenerate, necrotic, and effaced by neoplastic infiltrates. The jugular vein was ruptured in a focal area with adjacent hemorrhage and recanalization and fibroplasia at the edges of the rupture. Throughout the pulmonary parenchyma, there were small multifocal neoplastic cells corresponding with those found expanding the jugular vein. The remaining pulmonary parenchyma was congested with multiple extensive areas of hemorrhage and edema. The hepatic parenchyma had small foci of hemorrhage, sinusoid distension, and similar small neoplastic aggregates.
Photomicrographs of a section of the mass from the dog in Figure 1. The mass has infiltrated the lumen (dagger) of the jugular vein and has expanded the wall (asterisk) of the vein. Blood-filled vascular channels (double dagger) are formed by the neoplastic cells (section mark). H&E stain; bar = 200 μm. Inset—A section of the mass has a positive intracytoplasmic immunohistochemical reaction for factor VIII, as evidenced by the presence of brown granular pigment. Factor VIII-specific immunohistochemical stain; bar = 50 μm.
Citation: Journal of the American Veterinary Medical Association 255, 9; 10.2460/javma.255.9.1019
Photomicrograph of a section of the mass originating from the jugular vein in Figure 2. There are pleomorphic spindle-shaped cells that form blood-filled spaces (asterisk) and have variably distinct cell borders. Moderate to marked anisocytosis and anisokaryosis (arrowheads) and bizarre mitotic figures (arrows) are present. H&E stain; bar = 20 μm.
Citation: Journal of the American Veterinary Medical Association 255, 9; 10.2460/javma.255.9.1019
Morphologic Diagnosis and Case Summary
Morphologic diagnosis and case summary: hemangiosarcoma originating from the left external jugular vein wall with extensive surrounding hemorrhage and pulmonary and hepatic metastasis in a dog.
Comments
Hemangiosarcoma is a highly malignant neoplasm originating from vascular endothelial cells, which is commonly diagnosed in dogs.1–3 Hemangiosarcomas can develop in any tissue with blood vessels; in dogs, the most common primary sites include the spleen, right atrium, subcutaneous tissue, and liver. Other affected sites include lungs, kidneys, oral cavity, muscles, bones, urinary bladder, intestines, pulmonary arteries, aorta, left ventricle, uterus, prostate, and peritoneum.2,4 In the dog of the present report, the neoplasm originated from the external jugular vein; to the authors' knowledge, hemangiosarcoma at this site has not been previously reported.
In the case described in the present report, gross and histopathologic findings were consistent with hemangiosarcoma and metastatic disease of the liver and lungs. Grossly, visceral hemangiosarcoma is poorly circumscribed, nonencapsulated, and friable. Masses vary in size, can be pale gray to dark red or purple, and are soft or gelatinous with blood-filled or necrotic areas.5 Histologically, immature pleomorphic endothelial cells that form vascular spaces containing moderate to extensive areas of hemorrhage and necrosis are consistent with hemangiosarcoma.5 Tumor-associated blood vessels are typically tortuous and malformed, with blood pooling and presence of thrombi.2,4,5 Tumors usually infiltrate surrounding normal tissue as well as give rise to distant metastasis, as was observed in the dog of the present report. If the histologic features of a mass are insufficient for a definitive diagnosis of hemangiosarcoma, immunohistochemical staining for von Willebrand factor (factor VIII-related antigen) or cluster of differentiation 31 (CD31) accurately identifies endothelial cells and supports a diagnosis of hemangiosarcoma.2,4,6,7
Clinical signs associated with visceral hemangiosarcoma in dogs depend on tumor location and may include weakness, tachycardia, tachypnea, and pale mucous membranes (the latter being a result of anemia, which may be related to blood loss if the tumor ruptures).1,4,8 Clinicopathologic findings may include the presence of schistocytes and acanthocytes, regenerative or nonregenerative anemia, neutrophilia, mild to severe thrombocytopenia, hypoproteinemia, and mildly high liver enzyme activities.4,8,9 Effusion associated with visceral hemangiosarcoma is usually serosanguineous or frank blood that does not clot.2,4,5,9
For dogs with hemangiosarcoma, the prognosis is determined by primary tumor location and disease staging. The biological behavior of primary visceral tumors is aggressive with local tissue invasion and metastasis, both of which occur early in the disease; metastases are most commonly found in the liver, omentum, and lungs.1–4,6,9,10 Median survival time of dogs with visceral tumors that undergo surgical treatment alone is approximately 3 weeks to 2 months; with the addition of certain types of chemotherapy to the treatment regimen, the median survival time of affected dogs is 3 to 6 months.1–4,10 The case described in the present report illustrated the characteristically aggressive biological behavior of hemangiosarcomas and indicated that such neoplasms can develop in anatomic locations not typically associated with this disease process.
References
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