Tentative diagnosis spirocercosis: parasite-triggered esophageal mass in a Magyar Vizsla Introduction Spirocerca lupi is a nematode found all over the world, with a high prevalence in tropic and subtropic areas. This parasite is not known to be indigenous to Austria and to the authors' information so far only one case of spirocercosis has been reported in this country. Clinical signs associated with, infection only occur in carnivores, especially in canides. After oral infection by ingestion of an infected alternate host (coprophagous beetles) or paratenic host (e.g. birds, lizards, rodents), acute vomiting can occur because of migration of larvae through the stomach wall. The juvenile parasites reach the intrathoracic aorta via gastric arteries and maturate there for approximately 100 days. Now subadult, the nematodes infest the esophageal wall, forming parasitic nodules. Within 3 to 9 months, adult female parasites, who perforate the esophageal mucosa to deposit their eggs in the lumen, can be found within the lumps. Uncomplicated cases may remain subclinical, in others regurgitation and dysphagia can develop. Untreated, this condition can lead to conversion of the initially inflammatory masses to fatal sarcomas with formation of pulmonary metastasis and hypertrophic osteopathy. Case report A 1-year-old Magyar Vizsla was referred to the University of Veterinary Medicine Vienna with a history of regurgitation, pyrexia and lethargy. The dog had been imported from Hungary as a puppy and had not left Austria since then. Diagnostic work-up included esophagoscopy which revealed several lumps partially occluding the esophageal lumen. Multiple biopsies were obtained for pathohistologic evaluation. Lightmicroscopic analysis yielded multiple parasitic objects embedded in pyogranulomatous inflammatory tissue, allowing for the tentative diagnosis of Spirocerca lupi infection. The patient was treated with a total of 10 dosages of subcutaneous doramectin (in each case 500 mu g/kg) over a period of 8 months. Clinical signs subsided within few weeks, and a re-endoscopy carried out after the medication had been completed showed a full recovery. Conclusion Spirocercosis is a disease which may cause clinical signs not until the advanced stage has developed. Although clinical signs are often characteristic of this infection, it can be easily misdiagnosed especially in regions where Spirocerca lupi is rarely found. Given that early treatment is vital to allow for complete recovery and to prevent potentially fatal complications, spirocercosis should be considered as a differential in every dog with typical signs (especially regurgitation and dysphagia) even in low-risk-areas.