Multiple glucagon-producing pancreatic neuroendocrine tumors in a horse (Equus caballus).
Authors: Herbach N, Nagel L, Zwick T, Hermanns W
Journal: Veterinary pathology
Summary
# Editorial Summary Glucagon-secreting neuroendocrine tumors of the pancreas are vanishingly rare in equine medicine, making this 2014 case report from Herbach and colleagues particularly noteworthy as the first documented instance of multiple such tumours in a horse. The diagnosis was made incidentally during post-mortem examination of an animal euthanased for an unrelated dental infection, where pathologists identified up to 4 cm white nodules throughout the pancreatic tissue and subsequently confirmed their neuroendocrine origin through histological examination and immunohistochemical staining for glucagon, synaptophysin, chromogranin A, and neuron-specific enolase. Electron microscopy demonstrated characteristic electron-dense secretory granules consistent with normal pancreatic alpha cells, whilst additional findings included concurrent pheochromocytomas in the adrenal medulla, raising the possibility of a systemic neuroendocrine disorder. Whilst the horse in this case showed no documented clinical signs referable to glucagon oversecretion before death, the discovery underscores the potential for occult pancreatic neoplasia in equine patients and suggests that unexplained metabolic or clinical abnormalities warrant consideration of neuroendocrine tumours in the differential diagnosis. The concurrent adrenal pathology warrants further investigation into whether such cases represent a syndrome-related process in horses, comparable to multiple endocrine neoplasia syndromes documented in other species.
Read the full abstract on PubMed
Practical Takeaways
- •Pancreatic neuroendocrine tumors are extremely rare in horses and may be incidental postmortem findings; clinical significance in living horses remains unclear
- •Multiple endocrine tumors should raise suspicion for systemic neuroendocrine neoplasia; concurrent adrenal involvement may occur
- •This case establishes baseline pathologic criteria for diagnosing glucagon-producing neuroendocrine tumors in equines for future reference
Key Findings
- •First documented case of multiple glucagon-producing pancreatic neuroendocrine tumors in an equine
- •Tumors ranged up to 4 cm in diameter with positive immunoreactivity for glucagon, synaptophysin, chromogranin A, and neuron-specific enolase
- •Concurrent pheochromocytomas and adrenal hyperplastic foci were identified in the left adrenal gland
- •Electron microscopy confirmed electron-dense granules typical of pancreatic alpha cells within neoplastic tissue