Pituitary tumor diagnosis using gadolinium-enhanced magnetic resonance imaging in a dog with hyperadrenocorticism. A case report

Cushing’s disease is a common endocrine disorder of dogs, caused by persistent high concentration of cortisol in circulating blood. Almost eighty five percent of the cases of spontaneous hyperadrenocorticism in dogs are the result of a functional pituitary tumor or hyperplasia. Advanced imaging techniques like computed tomography (CT) or magnetic resonance imaging (MRI) are the best means to obtain a diagnosis of a pituitary tumor in dogs with pituitary-dependent hyperadrenocorticism (PDH). Moreover these imaging techniques are required to asses the size and location of the pituitary tumor when planning surgical removal of the tumor mass or of the complete pituitary gland. In Colombia, the use of these imaging techniques is very limited in the small animal practice, but it has recently become available for veterinary patients thanks to agreements with human clinical institutions. This report describes the case of an eleven year-old golden retriever with PDH as a result of a functional pituitary tumor, visualized by magnetic resonance imaging using gadolinium as contrast agent.

Central nervous system metastasis of a cutaneous epitheliotropic lymphosarcoma in a dog.

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 humanely destroyed. 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. Skin 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.