Successful surgical separation of asymmetrical caudal duplication or parasitic twinning in a kitten.

Case summary: A female kitten with two ectopic supernumerary pelvic limbs arising from the umbilicus was born in our clinic. Five weeks after the kitten's birth, she showed an acute deterioration in condition, with clinical signs of an ileus in the intestines entering the supernumerary body part. We then performed a surgical separation of the supernumerary limbs and intestines. Based on clinical findings and radiography, the kitten was classified as a case of parasitic twinning-omphalopagus or a subtype of asymmetrical caudal duplication, rather than a case of polymelia. Parasitic twinning and caudal duplication are rare congenital malformations in many animal species and in humans, which can often have a poor outcome. Almost 1 year after the separation, the cat appeared to be living a normal life without complications.

Relevance and novel information: A good outcome is rare in parasitic twinning because many of these animals present with other concurrent health issues, such as congenital heart malformation or cleft palate, or they are stillborn. However, this pathological entity is scarce in small animal medicine, and there is no documented survival rate. To our knowledge, this is the first officially documented case of parasitic twinning-omphalopagus in a cat in the past decade.