title: A liver schwannoma observed in a female Sprague-Dawley rat treated with MNU.
abstract: 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.
  
  
  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.
  
  
  CONCLUSIONS
  The tumor was a schwannoma with the origin in the Glisson's capsule.
authors: Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
authors: Catarina Isabel
authors: CI
authors: Teixeira-Guedes
authors: Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
authors: Ana Isabel
authors: AI
authors: Faustino-Rocha
authors: Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
authors: Daniela
authors: D
authors: Talhada
authors: Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport Sciences, University of Porto, Porto, Portugal.
authors: José Alberto
authors: JA
authors: Duarte
authors: Organic Chemistry of Natural Products and Agrifood, Mass Spectrometry Center, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
authors: Rita
authors: R
authors: Ferreira
authors: Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Animal and Veterinary Research Center (CECAV), University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
authors: Fernanda
authors: F
authors: Seixas
authors: Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Center for the Study of Animal Sciences (CECA), University of Porto, Porto, Portugal. Electronic address: pamo@utad.pt.
authors: Paula Alexandra
authors: PA
authors: Oliveira
mesh_terms: D000818:Animals; D005260:Female; D006548:Hernia, Diaphragmatic / Q000150:complications* / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000150:complications / Q000473:pathology; D008770:Methylnitrosourea / Q000633:toxicity*; D009442:Neurilemmoma / Q000139:chemically induced* / Q000150:complications / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D008770:Methylnitrosourea
keywords: Diaphragmatic hernia; NSE; Rat; S-100 protein; Schwannoma; Vimentin