Colonic ganglioneuromatosis in a horse.
Authors: Porter B F, Storts R W, Payne H R, Edwards J F
Journal: Veterinary pathology
Summary
Ganglioneuromatosis (GN) is an exceptionally rare neoplastic condition in horses, characterised by regional proliferation of benign neural tissue arising from the enteric nervous system, yet it remains poorly understood and frequently overlooked in diagnostic frameworks. Porter and colleagues documented a case of colonic GN in an 8-year-old horse, wherein a 25-cm segment of small colon developed multiple nodular proliferations composed of well-differentiated neurons, Schwann cells, enteric glial cells, and supporting connective tissue, with lesions extending from the myenteric plexus through the muscular wall to the serosal surface. Immunohistochemical and electron microscopic analysis confirmed the benign neural origin, with neurons staining positive for neuron-specific enolase and S-100 protein, whilst Schwann cells and glial elements expressed S-100 and glial fibrillary acidic protein (GFAP). Although GN carries a favourable prognosis given its non-malignant character, its physical presence within the colonic wall poses potential obstruction and dysmotility risks that warrant clinical consideration. Equine practitioners should recognise GN as a differential diagnosis when confronted with space-occupying lesions of the equine gastrointestinal tract, particularly when imaging or exploratory findings reveal nodular serosal proliferations, as early identification may guide surgical planning and prognostication.
Read the full abstract on PubMed
Practical Takeaways
- •When encountering segmental nodular lesions of the small colon at surgery or necropsy, ganglioneuromatosis should be considered as a rare differential diagnosis
- •Definitive diagnosis requires histopathology with immunohistochemical confirmation using NSE, S-100, and GFAP staining
- •The pathogenesis remains poorly understood; clinical presentation and outcomes are not detailed in this case, limiting treatment guidance
Key Findings
- •Ganglioneuromatosis presented as a 25-cm segmental proliferation of nodules in the small colon of an 8-year-old horse
- •Histopathology revealed well-differentiated neurons, Schwann cells, and enteric glial cells organized in fascicles with thick perineurial collagen
- •Immunohistochemistry confirmed neuronal origin with NSE and S-100 positive neurons, and S-100 and GFAP positive Schwann and glial cells
- •Ganglioneuromatosis is a rare equine condition that should be considered in differential diagnosis of gastrointestinal tumors