The "human tail": a rare cause of tethered cord: a case report.

Abstract

Observational case report. To report a case of dorsal cutaneous appendage or the so-called human tail that was the cause of tethered cord syndrome. The dorsal cutaneous appendage, or so-called human tail, is often considered to be a cutaneous marker of underlying occult spinal dysraphism. In such cases, there is usually a separate underlying tethering lesion. There have been only three case reports in the literature where this appendage itself was the tethering lesion. The fourth such case is being reported. An 11-month-old male child was brought for consultation for a "tail-like" structure in the low back since birth. Examination revealed a subtle thinning of the right lower extremity and a caudal appendage in the lower lumbar region. Plain radiographs revealed spina bifida at S1. MRI revealed a transitional lipoma at L5-S1 with a terminal syrinx. During surgery, a fibrous tract was seen extending from the base of the appendage through the defect in the bone and dura. The tract ended in the transitional lipoma of the cord at L5-S1. Sectioning of the tract and debulking of the transitional lipoma was done. After surgery, there was no change in the neurologic status of the patient. This case illustrates that the so-called "human tail" or the dorsal cutaneous appendage is not just a marker of underlying occult spinal dysraphism. In rare cases, the appendage itself can be the tethering lesion. In every case of dorsal cutaneous appendage, the surgeon should diligently search for the intraspinal extension of the lesion even if such an extension is not revealed by the MRI.