Ectopic dioctophymosis in a dog - Clinical, diagnostic and pathological challenges of a silent disease

A 9-month old, female, stray dog was rescued and conducted to a university veterinary hospital. Moderate anemia was observed and abdominal ultrasound revealed pancreatitis. Right kidney was not visualized due to intestinal gas. Urinalysis was normal. Castration was performed three weeks later. Before discharge, abdominal ultrasound was performed for internal sutures examination. A cyst-like structure was present in the right retroperitoneal space with what appeared to be tubular worms inside it, not observed in previous evaluation. An ectopic dioctophymosis diagnosis was made. Two female Dioctophyme renale were surgically removed from the structure. Right kidney was hyperemic but not removed. No sign of peritonitis was observed. The dog recovered well. Laboratory follow-up showed no abnormalities a year after the episode and Doppler ultrasound revealed a mild right nephropathy. This is the first canine ectopic dioctophymosis case with only an abdominal cyst-like structure containing viable nematodes, successfully treated. It represents the rarity and difficulties in diagnosing ectopic dioctophymosis even in enzootic locations, highlighting the importance of ultrasonographic screening for such silent, potentially zoonotic disease.