A liver schwannoma observed in a female Sprague-Dawley rat treated with MNU.

BACKGROUND: Schwannoma is a tumor of the nervous system composed by Schwann cells. It can occur naturally in several tissues of the body in both humans and animals. Diaphragmatic hernia can be congenital or acquired and is defined as a protrusion of abdominal viscera into the thoracic cavity.

MATERIALS AND METHODS: The animal was a female rat from an experiment of mammary tumor chemically induced. It was injected with N-methyl-N-nitrosourea (MNU) and died spontaneously at 22 weeks of age.

RESULTS: The animal had a diaphragmatic hernia and a hemorrhagic and multicystic mass in the liver herniated lobule. Microscopically the liver displayed a well circumscribed mass that was a tumor with hemorrhagic areas, necrosis and Antoni A and Antoni B patterns. It also displayed occasional positivity to vimentin and diffuse positivity to S-100 and NSE.

CONCLUSION: The tumor was a schwannoma with the origin in the Glisson's capsule.