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

Congenital Spinal Lipomatous Malformations. Part 2. Differentiation from Selected Closed Spinal Malformations

BACKGROUND

Congenital spinal lipomatous malformations (spinal lipomas, lipomyeloceles, and lipomyelomeningoceles) are closed neural tube defects over the lower back. Differentiation from some other closed neural tube defects in this region can be problematic for pathologists.

MATERIALS AND METHODS

This review is based on PubMed searches of the embryology, gross and histopathologic findings, and laboratory reporting requisites for retained medullary spinal cords, coccygeal medullary vestiges and cysts, myelocystoceles, true human vestigial tails, and pseudotails for comparison with congenital spinal lipomatous malformations.

RESULTS

Embryology, imaging, gross and histopathology of these closed neural tube lesions have different but overlapping features compared to congenital spinal lipomatous malformations, requiring context for diagnosis.

CONCLUSION

The lipomyelocele spectrum and to some degree all of the malformations discussed, even though they may not share gross appearance, anatomic site, surgical approach, or prognosis, require clinical and histopathologic correlation for final diagnosis.

Proposed caudal appendage classification system; spinal cord tethering associated with sacrococcygeal eversion

INTRODUCTION

The most commonly used classification system for caudal appendages (aka human tails) dates from the 1980s and classifies appendages (tails) as either true tails or pseudotails. Advances in neuroimaging since the 1980s, however, as well as an ever-increasing number of reported cases, have made this system outdated. Sacrococcygeal eversion is a condition in which the distal sacral and coccygeal vertebrae are curved in a retroverted rather than anteverted direction. It can give rise to one type of caudal appendage. Sacrococcygeal eversion has never been associated with spinal cord tethering in any previously published reports.

METHODS

We reviewed all cases of caudal appendage encountered by pediatric neurosurgeons at Children's Hospital Colorado since 2000 in which the appendage would be classified as a true tail by the most commonly used system mentioned above. We also reviewed cases of sacrococcygeal eversion encountered since 2000 by the same group of pediatric neurosurgeons. We searched the hospital electronic medical record system for additional appendages using the terms "caudal appendage" and "persistent human tail."

RESULTS

We found 9 "true" tails (as classified by the most commonly used system). All 9 were associated with tethering or possible tethering of the spinal cord and 6 were associated with a low-lying conus medullaris. There were 8 cases of sacrococcygeal eversion, including 2 associated with Apert or Pfeiffer syndrome and fibroblast growth factor receptor 2 (FGFR2) mutations; these have previously been reported. There was a single case of sacrococcygeal eversion associated with Goldenhar or Turner syndrome; the former was associated with a potentially tethering lesion. Four cases of sacrococcygeal eversion not associated with any known syndrome were also found; two of these were associated with tethering or potentially tethering lesions.

CONCLUSIONS

Most so-called true tails are likely cutaneous markers for spinal dysraphism and spinal cord tethering and are not remnants of the embryonic human tail. Sacrococcygeal eversion can be associated with spinal cord tethering. Based on our cases, and on review of the literature, we devised a five-category classification system for caudal appendages: (1) soft-tissue caudal appendages, (2) bony caudal appendages, (3) bony caudal prominences, (4) true tails, and (5) "other" caudal appendages.

Enigmatic human tails: A review of their history, embryology, classification, and clinical manifestations

The presence of a human tail is a rare and intriguing phenomenon. While cases have been reported in the literature, confusion remains with respect to the proper classification, definition, and treatment methods. We review the literature concerning this anatomical derailment. We also consider the importance of excluding underlying congenital anomalies in these patients to prevent neurological deficits and other abnormal manifestations.

[A rare case of caudal appendage]

Caudal appendage is a rare malformation which has since ever been interesting. We present the case of a girl in which a caudal appendage was discovered before birth. A throughout checking found an extension from this abnormality to the cordal spine. The baby is operated when 2months old. Differential diagnosis are spina bifida, teratoma and pilonidal sinus. Caudal appendage is one of the typical cutaneous finding with underlying spinal dysraphism, such as hair tuft or pigmented macule. The risk is a tethered cord syndrome that can lead to severe complication. The treatment is either surgery or expectation.

A bony human tail causing tethered cord syndrome: case report

INTRODUCTION

Dorsal cutaneous appendages, sometimes referred to as "human tails," are considered to be markers of underlying occult spinal dysraphism. Rarely, these tail-like structures can themselves be the cause of tethered cord syndrome. However, to date, a "bony human tail" causing tethered cord has not been reported in the literature. One such rare lesion is being reported.

DISCUSSION

A 2-days-old female child was brought for neurosurgical consultation with a skin-covered bony protuberance in the lower back. Examination of the child did not reveal any neurological deficits. Plain radiographic and CT evaluation showed a dorsal bony protuberance arising from the posterior elements of L1 vertebra. MRI showed the cord to be displaced posteriorly and adherent to the undersurface of the bony tail through a lipoma. During surgery, the bony "tail" was excised, and the cord was untethered with excision of the lipoma, which was tethering the cord to the bony "tail." When examined 1 year later, the child was developing normally without any focal neurological deficits.

CONCLUSIONS

This case is being reported for its rarity and to highlight the hitherto unreported occurrence of "bony human tail" causing tethered cord syndrome.

A gelatinous human tail with lipomyelocele: case report

We report a female infant who presented with a tail appendage bearing a gelatinous tip and an associated lipomyelocele. Magnetic resonance images revealed the presence of spina bifida and a tract in continuity from the tail to the conus medullaris. The tail was surgically removed. A human tail may be associated with underlying spinal dysraphism. Magnetic resonance or computed tomographic imaging is required in such cases for complete evaluation. This is the first case report of gelatinous-tip human tail.

Retained medullary cord in humans: late arrest of secondary neurulation

BACKGROUND

Formation of the caudal spinal cord in vertebrates is by secondary neurulation, which begins with mesenchyme-epithelium transformation within a pluripotential blastema called the tail bud or caudal cell mass, from thence initiating an event sequence proceeding from the condensation of mesenchyme into a solid medullary cord, intrachordal lumen formation, to eventual partial degeneration of the cavitatory medullary cord until, in human and tailless mammals, only the conus and filum remain.

OBJECTIVE

We describe a secondary neurulation malformation probably representing an undegenerated medullary cord that causes tethered cord symptoms.

METHOD

We present 7 patients with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac, complete with issuing nerve roots, which, except in 2 infants, produced neurological deficits by tethering.

RESULTS

Intraoperative motor root and direct cord stimulation indicated that a large portion of this stout neural structure was "redundant" nonfunctional spinal cord below the true conus. Histopathology of the redundant cord resected at surgery showed a glioneuronal core with ependyma-lined lumen, nerve roots, and dorsal root ganglia, corroborating the picture of a blighted spinal cord.

CONCLUSION

We propose that these redundant spinal cords are portions of the medullary cord normally destined to regress but are here retained because of late arrest of secondary neurulation before the degenerative phase. Because programmed cell death almost certainly plays a central role during degeneration, defective apoptosis may be the underlying mechanism.

Coexistence of a human tail and congenital dermal sinus associated with lumbosacral lipoma

We present a female baby with a human tail associated with congenital dermal sinus (CDS) at the caudal site of the tail. Magnetic resonance (MR) images with constructive interference in steady-state (CISS) sequencing clearly demonstrated a lumbosacral lipoma of caudal type, contiguous with the dermal sinus tract and not with the human tail. At 3 months old, the tail was surgically removed. The dermal sinus tract and contiguous lipoma were also resected, and untethering of the spinal cord was performed. Although both the human tail and CDS are frequently associated with spina bifida occulta, coexistence of the tail and CDS is exceedingly rare. CISS-MRI is useful for demonstrating the precise anatomical relationship between these complicated pathologies.

Thoracic lipomeningocele associated with diastematomyelia, tethered spinal cord, and hydrocephalus

Accessory human tails are uncommon malformations consisting of meningeal and neural structures and possibly occult spinal dysraphism (pseudotails). The thoracic location of a lipomeningocele constituting a pseudotail is very rare. The authors report the case of a young boy harboring a thoracic dorsal appendage consisting of a lipomeningocele and a dermoid cyst that was complicated by the presence of diastematomyelia, tethered spinal cord, syringomyelia, and mild hydrocephalus. The preoperative moderate ventricular dilation was decompressed by the surgical repair of the spinal malformation and required a specific treatment. The authors discuss the rare association of these clinical entities and conclude that complete spine and brain neuroimaging studies are necessary for the correct surgical planning of this kind of malformation.

The ‘human tail’ causing tethered cervical cord

STUDY DESIGN

Human tails continue to elicit curiosity till the present times. A unique case of human cervical dysraphism is described.

OBJECTIVES

In addition to the cosmetic stigma, these cutaneous markers provide a lead to reach the underlying spinal dysraphic states.

SETTING

Plains of North India.

METHODS

A case of human tail at the neck region is presented, whose cutaneous deformity lead the clinicians to his underlying spinal dysraphic state.

RESULTS

The final outcome of the patient was favorable.

CONCLUSION

Such markers should always be looked upon with a caution. The present report describes a unique case of a human neck tail, a causing cervical cord tethering.

Teratoma in human tail lipoma

We report a case of a rare congenital teratoma that developed in a lipoma attached to a remnant human tail. A male newborn baby presented with a large, 3-cm mass with an open margin, which pedunculated from a tail attached to the midline skin of the coccygeal area. Magnetic resonance images demonstrated multiple sacral spinal bifida without cord tethering, and also showed neural roots and a lipoma and teratoma with peripheral homogeneous high density and internal low density on T(2)-weighted images. Intraoperatively, we found and dissected two nerve roots from the filum terminale which extended into the mass. Pathologic examination of the mass revealed abnormal differentiation of respiratory epithelium and squamous cell metaplasia along the open margin of the mass, and mainly lipoma in the rest of the mass. We suggest that this case could support the hypothesis of transient teratomatous cells in the pathogenesis of the spina bifida with lumbosacral lipoma.