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Journal of Pediatric Surgery (2008) 43, E41–E43

The human tail: rare lesion with occult spinaldysraphism—a case reportDeepak Kumar Singha,⁎, Basant Kumarb, V.D. Sinhaa, H.R. Bagariaa

aDepartment of Neurosurgery, S.M.S. Medical College, Jaipur, Rajasthan 302004, IndiabDepartment of Pediatric Surgery (SPMCHI), S.M.S. Medical College, Jaipur, Rajasthan 302004, India

Received 27 March 2008; revised 18 April 2008; accepted 18 April 2008

Abstract Human tail or tail-like caudal cutaneous appendage is a rare fingerlike, midline protrusion at

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Key words:Human tail;Occult spinal dysraphism;Cutaneous appendage

the lumbosacrococcygeal region, often associated with occult spinal dysraphism. A 2-month-old malechild presented here had a lumbosacral tail-like appendage with underlying spinal dysraphism withoutany appreciable neurological deficit. In contradiction to a previous report, true vestigial tails are notbenign because they may be associated with underlying dysraphic state. About 50% of the cases wereassociated with either meningocele or spina bifida occulta. Management of such lesions must includecomplete neurological history and examination as well as magnetic resonance or computed tomographicimaging. After diagnosis, microsurgery should be performed if there is any intraspinal component toavoid any damage and neurological deficit.© 2008 Elsevier Inc. All rights reserved.

Skin lesions associated with spinal dysraphism are a well-documented finding. A “vestigial tail” describes a remnant of

growth resembling a tail apparent since birth. He was the firstoffspring of a 32-year-old healthy mother.

a structure found in embryonic life or in ancestral forms [1].A skin appendage resembling tail in a human is a very rarecondition and is usually consist of an underlying lipoma orlipomyelomeningocele [2]. This article will discuss ourexperience with a case of human tail with underlyinglipomyelomeningocele and review the literature.

1. Case report

A 2-month-old male child born after an uncomplicatedfull-term pregnancy, weighing 3.8 kg, was admitted in ourinstitute with an elongated, midline, lumbosacral, cutaneous

⁎ Corresponding author. Tel.: +91 9352536809 (Mobile).E-mail address: gkp.deepak@gmail.com (D.K. Singh).

022-3468/$ – see front matter © 2008 Elsevier Inc. All rights reserved.oi:10.1016/j.jpedsurg.2008.04.030

The baby had normal neurological examination withoutany deficit in both lower limbs, but some weakness inanal sphincter tone was appreciated. Local examinationrevealed a skin-covered, soft, nontender, nonfluctuatingappendage 2.2 × 7.5 cm in diameter located in the midlineof the lumbosacral region, appearing like a human tail(Fig. 1).

Plain x-ray of the spine demonstrated normal bonystructures. Magnetic resonance imaging (MRI) of the spineshowed spinal dysraphism in the form of spina bifida at L5and S1 vertebrae with lipomeningomyelocele and low-lyingtethered spinal cord with prominent central canal of lowerspinal cord (Figs. 2 and 3). Nerve conduction studies weresuggestive of demyelination and axonal sensory motorpolyneuropathy.

During operation, a midline vertical incision was givenencircling the base of appendage. The subcutaneous lipomawas excised along with its intradural components. The dural

Fig. 1 Lumbar tail measuring 2.2 × 7.5 cm.

Fig. 2 The MRI T2 coronal image showing lipomeningomyelocele (lipomatous component passing through dura marked witharrow head) with dilated lower central canal (white arrow).

E42 D.K. Singh et al.

opening was extended caudally, and detethering of filumterminale was done. The dura was closed in watertightfashion using fascial graft along with layered closure of

Fig. 3 The MRI T2 sagittal image showing lipomeningomyelo-cele (short arrow) with low-lying tethered cord (long arrow).

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surgical wound according to standard protocol. Microsurgi-cal techniques were applied during the whole procedure.

Microscopic examination showed that the resected speci-men had mature adipose tissue with occasional nerves.

2. Discussion

The human tail is an ill-defined, rare, fingerlike, midline,interesting anomaly and very difficult to classify as either atrue (vestigial) tail or pseudotail [2,3]. Dao and Netsky [4]described the features to distinguish the true tails from thepseudotails. True tail contains adipose and connectivetissue, striated muscle, blood vessels, and nerves and iscovered by skin. Bone, cartilage, notochord, and spinalcord are lacking. It may be as long as 13 cm and can moveand contract. The pseudotail is an anomalous prolongationof the coccygeal vertebra, lipoma, teratoma, condrodystro-phy, or parasitic fetus. The true tail is the distal remnant ofthe embryologic tail, which is present between the fourthand seventh or eighth weeks of fetal development [5,6].Harrison [6] suggested that vestigial tail arise from thedistal unvertebrated mesodermal portion of the embryonictail. There are only 66 cases that have been reported inmodern literature [2].

Our case was associated with spina bifida with lipome-ningomyelocele and tethered spinal cord. There are only 5

E43The human tail

cases of human tail and intraspinal lipoma causing tetheringof spinal cord reported in the literature [5]. Reviews of casereports indicate spina bifida to be the most frequentcoexisting anomaly with both true tail and pseudotail [2,4].Tavaghi et al [7] reviewed 200 cases of occult spinaldysraphism and showed it to be associated with cutaneoussigns in more than 50% cases, and 41 cases hadsubcutaneous lipoma associated with spina bifida [1,5,7].They reported only 1 case of spinal dysraphism with tail-likecutaneous structure consisting cutaneous and intrathecallipoma [7]. In the case of spinal dysraphism with associatedtail-like caudal appendages, the tail consists of underlyingspinal lipoma or lipomyelomeningocele [1,2]. There havebeen 14 cases of such tail-like appendages with spinaldysraphism reported in the literature [1].

In contradiction to a previous report by Spiegelmannet al [3], true vestigial tails are not benign because theymay be associated with underlying dysraphic state.According to previous a series of 48 skin-coveredlumbosacral masses, 67% of cases were lipomas andlipomyelomeningocele, 25% lumbosacral and sacrococcy-geal teratomas, and 4% meningocele and 4% terminalmyelocystoceles [8]. Hoffman et al [9] had described thatfatty mass in the lumbosacral region is the most commonpresenting complaint in a series of 97 patients, and 5patients presented with tail-like caudal appendages. Lu et al[10] noted 59 cases with caudal appendages, and 50 % ofthe cases were associated with either meningocele or spinabifida occulta [10].

The distinction between the true tail and pseudotail onclinical examination is almost always dubious, and despite a

normal neurological examination, normal plain x-ray ofspine, and clinical classification of true tail, subfascialexploration may show tethered cord or lipomeningomyelo-cele as what occurred in our case. Hence, ignoring the type oftail, each individual case needs comprehensive preoperativeinvestigation, and surgical exploration of the intraspinalcontent should be done microsurgically to avoid any damageor neurological deficit.

References

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[3] Spiegelmann R, Schinder E, Mintz M, et al. The human tail: a benignstigma. J Neurosurg 1985;63:461.

[4] Dao AH, Netsky MG. Human tails and pseudotails. Hum Pathol 1984;15:449-53.

[5] Feridun A, Ersin E, Muzeyyen G, et al. Human tail. A rare lesion andpossible marker of intraspinal lipoma in adolescent and pediatric cases.WSJ 2006;1(2):84-7.

[6] Harrison RG. On the occurrence of tail in man. Johns Hopkins HospBull 1901;12:96-101.

[7] Tavaghi G, Ghandchi A, Hambrick G, et al. Cutaneous signs of spinaldysraphism. Arch Dermatol 1978;114:573.

[8] McLone DG, Naidich TP. Terminal myelocystocele. Neurosurgery1985;16:36-43.

[9] Hoffman HJ, Taecholarn C, Hendrick EB, et al. Management oflipomyelomeningoceles. J Neurosurg 1985;62:1-8.

[10] Lu FL, Wang PJ, Teng RJ. The human tail. Pediatr Neurol 1988;1988:230-3.