A case of pseudo-human tail with nevus anemicus

A 15-day-old female baby presented with a tail-like structure on the buttocks since birth. Nevus anemicus was observed near the base of the structure. Neither vesicorectal disturbance nor any other neurological disorders were observed. We surgically resected the structure at the age of 1 month, and a diagnosis of pseudo-human tail was made histopathologically. During the follow-up period, we noted a protrusion at that site and consulted a neurosurgeon on suspicion of spina bifida. MRI revealed a lipoma in the spinal canal adhering to the spinal cord. She underwent excision of the tumor under general anesthesia. Her post-operative course was uneventful and she experienced no neurological disorders except for transient urinary retention. Human tail is divided into two groups:true human tail, which contains vertebrae and pseudo-human tail, which does not contain vertebrae. Most cases of pseudo-human tail are accompanied by various complications including spina bifida. Careful assessment using CT or MRI is necessary before surgery.