Intestinal Adenomatosis in a Foal
G. E. DUHAMEL and E. B. WHEELDONA thin six-month-old male Arabian foal was admitted to the Veterinary Medical Teaching Hospital, University of California, Davis, with a four-day history of anorexia, depression, and copious black feces. It had been at pasture with its mother since birth. One week prior to presentation, it had been wormed with Equivet (Farnam, Phoenix, Ariz.). On presentation, the animal was in lateral recumbency with cold extremities, pale injected mucous membranes, and marked soiling of the perineum and tail. Despite intensive fluid, steroid, and antibiotic therapy, the animal deteriorated rapidly and died twelve hours after presentation.The necropsy was done three hours later and revealed gross lesions in the stomach, small intestine, and kidneys. The entire gastrointestinal tract was filled with green pasty contents, and there were no formed feces in the rectum. The pyloric region of the stomach had several small and two large (3 cm X 1 cm) hemorrhagic ulcers. The wall of the distal duodenum, jejunum, and ileum was thickened irregularly (up to 12 mm) with prominent corrugation of the mucosal surface. An area involving proximal to mid ileum had a scattered segmental distribution of mucosal flattening; here, multiple often confluent nodules, with depressed centers 3 to 7 mm in width and raised a few mm above the flattened mucosal surface, were seen ( fig. I). The large intestine was not involved. Mesenteric lymph nodes were swollen and slightly congested while both kidneys had multiple early cortical infarcts.Tissue blocks were fixed in 10% neutral buffered formalin, embedded in paraffin, and cut at 6 pm. In addition to sections stained with hematoxylin and eosin (HE), sections of intestine were stained further with periodic acid-Schiff (PAS), Levaditi-Manovelian method, BrownBrenn tissue Gram's stain, Giemsa, and Ziehl-Neelsen acid-fast stain. Selected pieces of formalin-fured intestine were post-fixed in osmium tetroxide and embedded in epoxy resin. Thin sections were stained with uranyl acetate and lead citrate.Histologically, the small intestine had extensive irregular thickening of the mucosa due to marked hyperplasia of crypt epithelium. Villous length often was reduced, while intestinal