Hamartomas of the alimentary tract in dogs: A case series

Hamartomas are benign proliferations of disorganized tissues normally present in a given site. This study aimed to characterize histopathological features of alimentary tract hamartomas in dogs, focusing on their classification and diagnostic methods. Samples collected from 2 veterinary archives were evaluated using hematoxylin and eosin (HE), Masson's trichrome (MT), Gomori, and Luxol fast blue stains. Immunohistochemistry was performed for α-smooth muscle actin (SMA), neurofilament, GFAP, neuron-specific enolase, von Willebrand factor, and c-kit. Sixteen hamartomas were identified: 6 neuromuscular and vascular hamartomas, 9 neurovascular hamartomas, and 1 vascular hamartoma. Locations included the oral cavity (6/16) and the gastrointestinal tract (10/16). Most dogs were mixed breeds (8/16) with a median age of 10.5 years. These findings suggest that hamartomas should be included in the differential diagnosis of oral and gastrointestinal masses in dogs. For accurate classification and diagnosis, MT in combination with α-SMA and neurofilament immunohistochemistry is recommended, in addition to routine HE.