Multiple Peripheral Nerve Sheath Tumors in the Small Intestine of a Horse

Abstract

Abstract. Multiple neurofibromas, schwannomas, and hyperplastic enteric plexuses were observed in the distal jejunum and ileum of a 6-year-old pinto gelding. The animal was presented because of an acute episode of colic. Three meters of distal small intestine, partially incarcerated in the epiploic foramen, were surgically removed. Numerous tumor nodules up to 10 mm in diameter were found adjacent to a Meckel's diverticulum, predominantly located in the subserosa of a hypertrophic segment. Histologically, tumors were well demarcated and composed of interlacing fascicles formed by spindloid cells. Adjacent enteric plexuses were hyperplastic. Immunohistochemically, all tumors were positive for vimentin and S-100. Desmin immunoreactivity was only observed in larger tumors (> 500 pm). Glial fibrillary acid protein was demonstrated nearly exclusively in smaller ones. Immunostaining for neurofilament was restricted to entrapped ganglion cells. Based on conventional light microscopic examination and immunohistochemical evaluation, the lesion was diagnosed as multiple benign peripheral nerve sheath tumors in the small intestine.Key words: Enteric plexuses; horses; immunohistochemistry; neurofibroma; peripheral nerve sheath tumor; schwannoma; small intestine.Human tumors of the peripheral nerve sheath are divided into schwannomas, neurofibromas, and malignant peripheral nerve sheath tumors.(* In domestic animals, the preferred term for peripheral nerve sheath tumors is benign or malignant ~chwannoma.~.Il These rare neoplasms are most commonly encountered in cattle and dogs, where they develop predominantly in association with cranial or spinal nerve roots or in the subcutis." Bovine schwannomatosis (= neurofibromatosis) is characterized by multiple tumors, which may involve the v i~c e r a .~. l~In horses, two cases of intestinal neurofibromas have been r e p~r t e d .~.~~ Both were solitary tumors arising in the colon. A small intestinal ganglioneuroma with proliferating nerve cells has also been described. I Here, the unusual finding of the simultaneous occurrence of multiple neurofibromas, a few schwannomas, and hyperplastic enteric plexuses in the distal small intestine of a horse is described.A 6-year-old pinto gelding was referred to the Clinic of Veterinary Medicine in Gescher-Hochmoor (FRG) for assessment of an acute episode of severe abdominal pain. First clinical signs of colic with pawing and looking at his flanks had been noticed 6 hours earlier. Physical examination revealed pulse rate of 100 beatdminute, respiratory rate of 32 breathdminute, and rectal temperature of 37.5 C. The packed cell volume was 30%, and total protein concentration was 6.8 g/dl. A nasogastric tube was passed, and 1 liter of fluid refluxed. No feces were found in the rectum. Rectal palpation revealed distended loops of small intestine in the caudal portion of the abdomen. Physical findings and diagnostic tests supported a clinical diagnosis of small intestinal strangulation. A ventral midline celiotomy was performed, and a mediolateral...

Gastrointestinal Stromal Tumors in Equids

“…This neoplasm was very similar to an equine small intestinal tumor that was classified as a peripheral nerve sheath tumor by others. 17 Within this spectrum of GIST, some tumors may arise within or in the vicinity of the intestinal plexi (inframuscular or submucosal), as appeared to be the case with the neoplasm of animal No. 8.…”

Gastrointestinal Stromal Tumors of the Equine Cecum

“…These tumors were classified as multiple benign nerve sheath tumors due to GFAP and S100 immunopositivity. 7 Multiple tumors were present in the cecum of one of the horses of this report; these tumors were thought to represent multiple sites of tumor development rather than metastasis.…”

The importance of clinical, histopathological and immunohistochemical marking for differential diagnosis of non-hematopoietic gastrointestinal mesenchymal neoplasms in dogs: literature review

“…Gastrointestinal neurogenic sarcomas are uncommon and have been reported in dogs and horses (KIRCHHOF et al, 1996;SCHÖNIGER;SUMMERS, 2009). These neoplasias usually involve the cranial nerves, spinal nerve roots or subcutaneous tissue more frequently than the segments of the gastrointestinal tract (CAMPBELL et al, 2003).…”

“…These neoplasias usually involve the cranial nerves, spinal nerve roots or subcutaneous tissue more frequently than the segments of the gastrointestinal tract (CAMPBELL et al, 2003). Neurogenic sarcomas are usually classified as neurofibrosarcoma and schwannoma (KIRCHHOF et al, 1996;HEAD et al, 2002). The World Health Organization has grouped neoplasms that originate from Schwann cells, fibroblasts or perineural cells, such as nerve sheath neoplasm that may be benign or malignant (HEAD et al, 2002;SCHÖNIGER;SUMMERS, 2009).…”