An unusual case of intestinal leiomyositis in a Bernese mountain dog.

A 1-year-old, female Bernese mountain dog was presented to the Veterinary Teaching Hospital of Turin University with a 3-month history of weight loss, intermittent anorexia, vomiting, constipation, and abdominal distension. Full-thickness biopsies from the stomach, duodenum, jejunum and ileum were collected for histological and immunohistochemical examination. Microscopic lesions displayed severe diffuse degeneration and loss of leiomyocytes, with lymphocytic leiomyositis, fibroplasia, angiogenesis, severe diffuse neuronal atrophy, and ganglioneuritis in the myenteric (Auerbach's) plexus. A diagnosis of chronic idiopatic intestinal pseudo-obstruction was made. Response to immunosuppressive therapy was poor and the dog was humanely euthanized. Unique findings were mononuclear infiltration composed predominantly of B-cell, angiogenesis and weak immunoreactivity for neuron-specific enolase.