Human tail associated with lipomeningocele--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.

Congenital Spinal Lipomatous Malformations. Part 1. Spinal Lipomas, Lipomyeloceles, and Lipomyelomeningoceles

Background: Lumbosacral spinal lipomas and lipomyeloceles are usually identified in early childhood. Terminology, histopathology, and diagnosis for these malformations can be confusing. Materials and Methods: This is a PubMed review with comparison of embryology, gross, and histopathology, and reporting requisites for these and related closed spinal malformations. Results: The spinal lipoma group (congenital spinal lipomatous malformations) includes subcutaneous, transdural, intradural, and noncontiguous malformations stretching through the entire lower spinal region. This lipomyelocele trajectory overlaps the embryonic tail's caudal eminence. Histopathologically, the lipomyelocele spectrum is a heterogeneous, stereotypical set of findings encountered from dermis to spinal cord. Diagnosis requires detailed correlation of images, intraoperative inspection, and histopathology. Conclusions: Appropriate terminology and clinicopathologic correlation to arrive at a diagnosis is a critical activity shared by pathologist and clinician. Prognostic and management differences depend on specific diagnoses. Familial and genetic influences play little if any role in patient management in closed spinal malformations.

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 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.

Terminal myelocystocele: surgical observations and theory of embryogenesis

BACKGROUND

The structural complexity of terminal myelocystocele (TMC) precludes a recognizable link to spinal cord development and therefore a plausible embryogenetic theory.

OBJECTIVE

To demystify TMC using clinical, imaging, surgical, electrophysiological, and histopathological data and to propose a theory of embryogenesis.

METHODS

Our series consisted of 4 newborns and 6 older children. All had preoperative magnetic resonance imagings and surgical repair of the myelocystocele with electrophysiological monitoring.

RESULTS

TMC can be deconstructed into essential and nonessential features. Essential features are present in all TMCs and constitute the core malformation, comprising an elongated spinal cord extending extraspinally into a cerebrospinal fluid--filled cyst that is broadly adherent to the subcutaneous fat. The functional conus resides in the proximal cyst or within the intraspinal cord, and the caudal myelocystocele wall is nonfunctional fibroneural tissue. Nonessential features include variable measures of hydromyelia, caudal meningocele, and fat, present in only some patients. The core structure of TMC strikingly resembles a transitory stage of late secondary neurulation in chicks in which the cerebrospinal fluid-filled bleblike distal neural tube bulges dorsally to fuse with the surface ectoderm, before focal apoptosis detaches it from the surface and undertakes its final dissolution. We theorize that TMC results from a time-specific paralysis of apoptosis just before the dehiscence of the cystic distal cord from the future skin, thereby preserving the embryonic state.

CONCLUSION

Besides tethering, the myelocystocele may show early rapid expansion causing precipitous deterioration. We recommend early repair with resection of the nonfunctional caudal cyst wall, reconstruction of the proximal neural placode, and duraplasty.

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.

Skin-covered midline spinal anomalies: a report of four rare cases with a discussion on their genesis and milestones in surgical management

BACKGROUND

The differential diagnosis for a dorsal midline mass presenting in a newborn encompasses a wide range of pathological conditions, including spinal dysraphisms, tumoral overgrowths including teratoma and hamartoma, disturbances in regression of fetal tail, and pseudotail formation.

OBJECTIVES

To present (a) three rare cases of human tails and one case of tethered cord due to a midline anomaly resembling part of a human limb, (b) to discuss different kinds of clinical and pathological conditions which may be encountered in such newborns, (c) to hypothesize a theory about genesis of these congenital lesions, and (d) to remind drawbacks in preoperative evaluations and surgical management of these newborns.

MATERIALS AND METHODS

Four newborns with dorsal midline malformations initially diagnosed as heterotopias are presented. Appropriate preoperative investigations and proper surgical interventions leading to resection of the lesions were performed. All four were skin-covered lesions containing well-differentiated cellular elements of fat, vascular, muscular, bony, and cartilaginous origin. Midline spinal dysraphism was detectable both pre- and intraoperatively only in one case in which cord untethering was also performed along with the first surgical intervention. In the other three "tailed cases," midline bone defect could not be detected in the available X-ray films; consequently, simple excision of the tail-like lesions was done. The first patient had to be explored for repeat untethering of the cord after 4 years, but the others have not yet developed any sign of tethering during an average period of 12 years follow-up.

CONCLUSION

Morphological diagnosis of these lesions is not easy, and the attending pediatrician and neurosurgeon should be familiar with the differential diagnosis of such lesions and be prepared for possible time-consuming operation mandatory to achieve total resection of the lesion in a newborn under general anesthesia. Reviewing the possible theories regarding the genesis of such anomalies, it is hypothesized and suggested that all similar cases could have been of hamartomatous origin rather than defects of embryogenesis.

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.

Human tail with noncontiguous intraspinal lipoma and spinal cord tethering: case report and embryologic discussion

Children born with a tail-like appendage have a rare malformation that is frequently associated with abnormalities of the spine and spinal cord. A contiguous fibrolipoma is usually seen extending from the subcutaneous portion of the tail into the inferior spinal cord, resulting in tethered cord syndrome. We present the case of a child born with a tail and intraspinal lipoma that were not contiguous with each other, and were separated by an intact layer of lumbosacral fascia. The tail and lipoma were removed and the spinal cord untethered, and the child is neurologically normal 2 years after surgery. The absence of a contiguous lipoma from the tail to the spinal cord suggests that this condition may be principally caused by a disorder of secondary neurulation and/or regression of the normal embryonic tail bud. The embryology of the lower spine is reviewed and possible etiologies discussed.

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

STUDY DESIGN

Observational case report.

OBJECTIVES

To report a case of dorsal cutaneous appendage or the so-called human tail that was the cause of tethered cord syndrome.

SUMMARY OF BACKGROUND DATA

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Ectopic fingerlike structure in the thoracic region. Case report

The authors present a case of a rare cutaneous lesion resembling a human finger that protruded from the posterior thoracic region of a 7-month-old girl who was examined after the fingerlike protrusion was noted at birth. The protrusion measured 3 cm in length and 1 cm in diameter. It was located at the level of T-12 and was surrounded by angiomatous and lipomatous tissue. A computerized tomography scan demonstrated three bones in the protrusion. including deformities of the T-9 and T-10 and T-11 dysraphism. Magnetic resonance imaging revealed a hyperintense signal on the T1-weighted sequence and a hypointense signal on the T2-weighted sequence, which was visualized at the attachment to the spinal cord from T9-11. After removal of the fingerlike structure and subcutaneous mass, a T10-11 laminectomy and removal of the intradural mass were performed. Histological examination showed that the appendage was composed of nail, three bones, cartilage, and normal skin. This appendage can be recognized not only as a variant type of caudal appendage but as an ectopic finger and fingernail. The authors discuss the developmental differences among the protrusion in the present case and ordinary caudal appendages.

The human tail

The human tail is a congenital anomaly with a protruding lesion from the lumbosacrococcygeal region. A newborn with a tail-like structure over the coccygeal area observed since birth is presented. Lipoma accompanied by tethered spinal cord were found. In reviewing the literature from 1960 to 1997, 59 cases were described. Higher incidences of spinal dysraphism (49.15%) and tethered spinal cord (20.34%) compared with previous reports were evident. This fact plays an important role in understanding the disturbance of development and regression of human tails. A new classification according to whether the anomaly appears in combination with spinal dysraphism is proposed for clinical usage. Preoperative detailed image studies are needed to clarify the possibility of tethered spinal cord syndrome developing in the future and thus prevent it. Magnetic resonance imaging is the modality of choice if available. Long-term follow-up for possible sequelae after operation, especially in cases with spinal dysraphism, is necessary.

True tail in a newborn

Human true tail is a rarely reported anomaly that may have a marked psychologic impact on the patient's family and may be associated with other congenital anomalies. A true tail in a newborn girl is reported, and findings from a review of the literature are summarized. The clinical and pathologic differential diagnoses are discussed, as they might affect the management and prognosis of this congenital malformation.