Leiomyosarcoma in an Adult Llama

Jarrod LudwigRD. Tyler Jr., D. Righter, K. Potter, KH. Baum, GK. Saunders Virginia-Maryland Regional College of Veterinary Medicine

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• 12-year-old neutered male llama

Signalment

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History and Clinical Signs

• Subsequently the llama was found dead

• Presented to the referring veterinarian with acute:– Lethargy– Anorexia– Ptyalism– Tachypnea

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Gross Lesions• Ruptured 15cm hepatic mass with a blood clot

adherent to the serosal surface

Liver

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Gross Lesions• 3-5cm, mottled, white-red nodules scattered

throughout the liver and lung

Lung

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Microscopic Description• Hepatic mass and pulmonary nodules

– Extensive hemorrhage, fibrin, edema, and necrosis

– Normal hepatic architecture is obliterated and replaced by a densely cellular mass of pleomorphic spindle cells arranged in streams and bundles

– Marked anisocytosis, anisokaryosis, occasional multinucleated cells, and 2-4 mitotic figures per 400x field

– These findings are consistent with a neoplasm of mesenchymal origin (sarcoma)Presented at SEVPAC 2008 –

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Microscopic Description

H&E histopathology of the hepatic nodulePresented at SEVPAC 2008 – Permission granted for use on

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H&E histopathology of the hepatic nodule

Microscopic Description

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Immunohistochemistry

• Neoplastic cells are positive for:– 60-85% Vimentin immunoreactivity– 10-15% Muscle-specific actin immunoreactivity– 15-20% α-smooth muscle actin immunoreactivity

• Neoplastic cells are negative for:– Mac 387– Desmin– Cytokeratin

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Immunohistochemistry - Markers

• Vimentin - demonstrates that the neoplasm was of mesenchymal origin (sarcoma)

• Muscle-specific actin - recognizes all of the alpha actins (skeletal, cardiac, and smooth muscle) as well as gamma smooth muscle actin

• α-smooth muscle actin - recognizes only alpha smooth muscle actin

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Immunohistochemistry

Liver - Muscle actinPresented at SEVPAC 2008 – Permission granted for use on

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Immunohistochemistry

Liver - α-smooth muscle actinPresented at SEVPAC 2008 – Permission granted for use on

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Case Summary

• The large hepatic mass is suspected to be the primary neoplasm

• The mass likely originated from the smooth muscle of either a hepatic blood vessel or biliary duct

• Immunohistochemistry and histopathology support a diagnosis of leiomyosarcoma

• Sudden death was the result of hypovolemic shock secondary to acute hemoabdomen caused by the rupture of the large hepatic mass

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References

1. Cooper BJ, Valentine, BA: Tumors of the muscle. In: Tumours in Domestic Animals, ed. Mueten DJ, 4th ed., pp 319-340, Iowa State Press, IA 2002

2. Shapiro JL, Watson P, McEwen B, Carman S: Highlights of camelid diagnoses from necropsy submissions to the Animal Health Laboratory, University of Guelph, from 1998 to 2004. Can Vet J 46:317–318., 2005

3. Valentine BA, Martin, JM: Prevalence of neoplasia in llamas and alpacas (Oregon State University, 2001–2006). J Vet Diagn Invest 19:202-204, 2007

4. Valero R, et al.: Leiomiosarcoma hepatico: Reporte de un caso y revision de la literature. Casos Clinicos de Gastroenterologia, Casos Clinicos de Oncologia 2006: http://www.portalesmedicos.com/publicaciones/articles/256/2/Leiomiosarcoma-hepatico.-Caso-Clinico 2006

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Questions?

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