Case description: A 10-month-old male crossbred dog presented with a 4-week history of polyuria and polydipsia and a 6-month history of vomiting.
Clinical findings: Clinical examination revealed abdominal pain and right-sided nephromegaly. Biochemistry was within normal limits. Diagnostic imaging showed a well-defined, unilateral renal mass containing anechoic fluid consistent with a simple renal cyst (SRC).
Treatment and outcome: The cyst was drained under ultrasonographic guidance but recurred 3 months later, concomitant with recurrence of the previously reported clinical signs. The cyst was then deroofed, fulgurated, and omentalized under laparoscopy by use of a 3-port technique. The resected cystic wall was histopathologically consistent with an SRC, presumptively congenital. The dog showed a good recovery with resolution of clinical signs. Renal function was normal at last follow-up, conducted 2 years postoperatively, without evidence of recurrent disease.
Clinical relevance: To our knowledge, this was the first report of a symptomatic juvenile SRC of presumptively congenital origin in a dog treated successfully by laparoscopic deroofing, fulguration, and omentalization. The polyuria, polydipsia, chronic vomiting, and abdominal pain may all have been related to space-occupying effects of the cyst, as these symptoms resolved post-treatment. Results of long-term follow-up advocate for this durable cure of SRC by use of laparoscopic procedures, especially when compared to simple drainage of the cyst, as the latter initially failed in the present case.