Species: Dog Strain/breeder: Mixed breed German sheperd dog Sex: Male Age: 9 years Study type: - Treatment: - Animal status: Humanely destroyed Clinical findings: Sudden blindness, pyrexia, hyperaemia of oral mucosa Organ(s): Oral mucosa, Brain Macroscopic finding(s): Oral mucosa: no abnormalities detectable Brain: Tumor mass in the ventral midline of the diencephalon effacing the optic chiasm and invading the hypothalamic area Staining: H&E, paraffin wax-embedded

Fig. 1 (90k) Fig. 2 (80k)

Abstract

S. CZASCH¹, K. RISSE² and W. BAUMGÄRTNER³

¹Merck KGaA, Institut für Toxikologie, Frankfurter Straße 250, 64293 Darmstadt, Germany
²Staatliches Medizinal-, Lebensmittel- und Veterinäruntersuchungsamt Mittelhessen, Gießen, Germany
³Institut für Pathologie, Tierärztliche Hochschule Hannover, Hannover, Germany

Key words: epitheliotropic T-cell lymphosarcoma, dog, CNS metastasis

This report describes an uncommon case of a cutaneous epitheliotropic T-cell lymphosarcoma with central nervous system (CNS) manifestations in a 9-year-old mixed breed German shepherd dog. The animal had a history of sudden blindness, pyrexia and multifocal areas of hyperaemia in the oral mucosa. A biopsy from the muco-cutaneous junction of the lips led to the diagnosis of an epitheliotropic lymphosarcoma and the animal was killed. At necropsy, hyperaemia in the oral mucosa was no longer detectable. In the brain, a mass effacing the optic chiasm and invading the hypothalamic area was found; histological examination revealed lymphoid tumour cell infiltration. In the epithelium of the oral mucosa, intra-epithelial lymphoid tumour cells, sometimes arranged in small clusters (Pautrier's microabscesses), in combination with a mild inflammation in the superficial dermis were observed. Oral mucosa and brain tumour cells expressed CD3 antigen, indicating their T-cell origin. This is, to our knowledge, the first report of a cutaneous epitheliotropic lymphosarcoma with CNS metastasis in a dog (CZASCH et al. J Comp Pathol 2000; 123: 59-63)