ABSTRACT
A 7-years-old intact female mixed breed dog was referred to the private veterinary clinic because of history of intense food regurgitation. The plain X-ray examination and the contrast-enhanced X-ray using barium sulfate revealed the presence of a radio-opaque mass in the final third of the esophagus. Stool samples were collected and the coproparasitological test was done, which showed thick-shelled eggs from Spirocerca lupi. As the canine died, the necropsy was performed, showing nodular lesions in the esophagus, compatible with the typical lesions of spirocercosis. The histopathological analysis showed the proliferation of spindle-shaped cells, process compatible with fibrosarcoma. This is the first official report of the presence of canine spirocercosis in Guapimirim city, Rio de Janeiro, Brazil, and can serve as a warning to veterinary practitioners, about this probably endemic region for S. lupi.