Coccygeal Pits Bradley E. Weprin, MD*‡§, and W. Jerry Oakes, MDʈ¶ ABSTRACT. Background. Congenital dermal sinuses ABBREVIATION. OSD, occult spinal dysraphism. represent cutaneous depressions or tracts that are lined by stratified squamous epithelium. They communicate between the surface of the skin and deeper structures utaneous abnormalities of the back may rep- and may occur anywhere along the craniospinal axis. resent underlying malformations of the spine. These sinuses are thought to result from abnormal sep- One such anomaly, the congenital dermal si- aration of the cutaneous and neural ectoderm between C nus, is a superficial depression or tract in the skin the third and fifth week of intrauterine life. They may be that is lined by stratified squamous epithelium. Its often accompanied by other cutaneous stigmata, various appearance can signify the presence of an abnormal dysraphic abnormalities, or intraspinal tumors. In the sacrococcygeal area, cutaneous congenital abnor- connection between the skin surface and subarach- malities are relatively common. It is estimated that 2% to noid space and/or an occult dysraphic state. This 4% of children harbor intergluteal dorsal dermal sinuses. potential communication places the child at addi- These intergluteal sinuses in the perianal region are fre- tional neurologic risk from meningitis, which can quently referred to as pits or dimples. Their cause is sometimes be recurrent. These congenital dermal si- considered similar to other congenital dermal sinuses nuses are frequently associated with other cutaneous and appears unrelated to acquired pilonidal conditions signatures, occult dysraphic lesions, or intraspinal observed in adults. They may become susceptible to local tumors. The natural history of such occult spinal recurrent infection from trauma or hirsutism. dysraphic abnormalities is variable and often unpre- Controversy regarding the evaluation and manage- dictable. Although some individuals remain asymp- ment of cutaneous defects in the coccygeal region exists. tomatic throughout adulthood, others may develop Methods. Both a literature review and a career review of clinical material were performed. Databases for arti- progressive dysfunction of the lower limbs and blad- cles published in English were surveyed for key words der. The insidious fashion in which such complica- relating to coccygeal sinuses using standard computer- tions develop may lead to irreversible damage before ized search techniques. The medical records of children any symptomatic manifestation. The risk of neuro- presenting to our neurosurgical clinic for evaluation of logic deterioration exists at all ages and increases dorsal dermal sinuses were reviewed to identify those with time and is frequently progressive.1–8 The de- with intergluteal sinuses. tection of such a subtle cutaneous anomaly in a child Results. In the evaluation of reported cases and of our may be crucial to future neurologic, urologic, and own, we were unable to identify any children with coc- orthopedic development. cygeal sinuses without other cutaneous markers other Congenital dermal sinuses may be difficult to than hair with findings suggestive of intraspinal commu- identify. They can be located anywhere along the nication. Conclusions. Intergluteal dorsal dermal sinuses are craniospinal axis. Embryologically, the lesions are relatively common lesions that frequently come to neu- thought to develop from faulty neurulation. The neu- rosurgical attention. They do not seem to be associated ral ectoderm incompletely separates from the cuta- with significant risk of spinal cord and intraspinal anom- neous surface ectoderm, a term referred to as incom- alies. Simple intergluteal dorsal dermal sinuses without plete dysjunction.9 Histologically, the sinus tract is other cutaneous findings do not require radiographic or lined by statified squamous epithelium with sur- surgical evaluation and treatment. If other markers or rounding dermal tissue. The majority of these lesions neurologic symptoms are present, however, radiographic occur in the lumbar or lumbosacral region followed evaluation may be indicated. Pediatrics 2000;105(5). URL: by the occipital and thoracic regions, respectively. http://www.pediatrics.org/cgi/content/full/105/5/e69; oc- They may extend rostral a considerable distance to cult spinal dysraphism, spina bifida occulta, dermal sinus, terminate several spinal segments above the cutane- pilonidal sinus. ous ostium.10 The dermal sinus tract may actually end blindly in the subcutaneous tissue or it may extend into the spinal canal, as it does in nearly one From *Children’s Medical Center of Dallas, Dallas, Texas; ‡Neurosurgeons half of cases. They are infrequently associated with for Children, Dallas, Texas; §Department of Neurological Surgery, Univer- sity of Texas-Southwestern Medical School, Dallas, Texas; ʈDepartment of complex vertebral abnormalities unless other forms Surgery, University of Alabama; and ¶Children’s Hospital of Alabama, of occult spinal dysraphism (OSD) are present. Birmingham, Alabama. In the coccygeal region cutaneous, congenital ab- Received for publication Jul 28, 1999; accepted Dec 20, 1999. normalities are relatively common (Fig 1). They are Reprint requests to (W.J.O.) Pediatric Neurosurgery, 1600 7th Ave S, ACC frequently referred to by multiple names (Table 1). It 400, Birmingham, AL 35233. E-mail: [email protected] ϳ PEDIATRICS (ISSN 0031 4005). Copyright © 2000 by the American Acad- has been determined that 2% to 4% of children emy of Pediatrics. harbor intergluteal dorsal dermal sinuses.11–14 These http://www.pediatrics.org/cgi/content/full/105/5/Downloaded from www.aappublications.org/newse69 by guestPEDIATRICS on September 30, Vol. 2021 105 No. 5 May 2000 1of5 spanned 2 academic institutions during the study. The clinical presentation, radiographic evaluation, and subsequent manage- ment of patients were studied to identify appropriate individuals for inclusion. The clinical evaluation consisted of a detailed neu- rological and general physical examination in all patients. A uniform definition was applied to the diagnosis of an isolated coccygeal pit: a cutaneous pit, dimple, or sinus located below the level of a symmetric intergluteal crease that is without the asso- ciated presence of any additional cutaneous anomaly. Children were excluded from additional review if hemangiomas, abnormal tufts of hair, areas of cutaneous hypo- or hyper-pigmentation, sinuses, dimples, or subcutaneous masses were identified any- where on the back in addition to the presumed coccygeal lesion (Fig 2). Children were also excluded by the presence of an asym- metric gluteal cleft. RESULTS Fig 1. Photograph of the low back and buttocks of an infant. A coccygeal pit is appreciated within the intergluteal crease. After an extensive and critical review of the En- glish literature, only 7 cases of cutaneous, coccygeal abnormalities associated with abnormalities of or ab- sinuses that occur below the natal cleft in the peri- normal communications with intraspinal contents anal region are frequently referred to as pits or dim- were identified (Table 1). These 7 individuals formed 13,15,24–26 ples. They may become susceptible to local recurrent the basis of 5 reports. Their clinical presenta- infection from trauma or hirsuitism. They are not tion varied. Six individuals presented with a neuro- related to acquired pilonidal conditions observed in logic infection, bacterial meningitis affected 5, and a adults.12 Their cause is not entirely understood. spinal epidural abscess occurred in another. The final Controversy regarding an association between patient was neurologically normal and without his- coccygeal pits and spina bifida or any communica- tory of antecedent infection but underwent prophy- tion with the subarachnoid space exists in the litera- lactic surgical exploration. An intradural dermoid ture. Some authors argue that the presence of any tumor was identified. cutaneous abnormality in the gluteal region warrants Our literature review suggests that the relative risk radiographic and/or surgical evaluation because of a of associated neurologic infection or deficit is exceed- suspected association with abnormal communica- ingly rare. Only 7 individuals have been reported in tions with or various abnormalities of the contents of the English literature to exhibit findings suggestive the intraspinal cavity.13,15–18 Some clinicians suggest of coccygeal pit in association with an intraspinal that the respective appearance of the lesion should abnormality or neurologic infection. Careful inspec- determine its further work-up. Lesions are inspected tion of these published reports may reduce this small for the ability to discern the cutaneous base or for the number even further. In 5 cases, the coccygeal abnor- 13,15,24 presence of hair.13 Others, however, believe that all mality was not in isolation. Additional dimples coccygeal dimples or sinuses are innocent and war- and/or sinuses above the intergluteal crease and rant no additional evaluation other than physical hemangiomas were documented. The risk of associ- examination.19–23 Hence, the proper evaluation and ated OSD and neurologic infection has been clearly management of these isolated cutaneous defects in demonstrated for such cutaneous abnormalities. The the coccygeal region are relatively uncertain. presence of coccygeal pit, shown to be quite com- Given the common occurrence of these cutaneous mon, may have been incidentally present in