Putative diagnosis of neuromuscular and vascular hamartoma: 2 cases in dogs and review of the veterinary literature.

Neuromuscular and vascular hamartoma (NMVH) is an infrequent gastrointestinal lesion described in human and veterinary medical literature. The histologic features of this entity are haphazardly arranged fascicles of smooth muscle, nerve fibers, scattered ganglion cells, and hemangiomatous blood vessels. Here we describe 2 putative cases of NMVH in a 1.7-y-old, intact female Anatolian mixed-breed dog and a 4-mo-old intact male Akita dog. Both animals had gastrointestinal clinical signs, including hematochezia, and on exploratory laparotomy, intussusception was confirmed. Histologic examination confirmed NMVH within the cecal wall in both cases using a panel of immunohistochemical (IHC) markers for vascular structures (CD31), smooth muscle (alpha-smooth muscle actin [α-SMA]), and nerves (glial fibrillary acidic protein [GFAP] and S100). The complete surgical excision of the lesion in both animals was considered curative without persistent clinical signs 14 mo and 12 mo, respectively, after surgery.