Empiric antibiotic coverage consisting of vancomycin and ceftazidime was started with concern for soft tissue infection potentially contiguous with the epidural space. Lumbosacral X-ray demonstrated prominent soft tissue posterior to the sacrum with no clear spinal abnormality (Figure 2). Ultrasound demonstrated a complex subcutaneous lesion superficial to the mid-sacrum, which likely represented an abscess but without exclusion of any communication with the lumbosacral spine (Figures 3 and 4). An MRI was performed for definitive imaging of this area with findings of a subcutaneous soft tissue abscess consistent with an infected pilonidal cyst (Figure 5). There was no epidural extension or evidence of spinal dysraphism.
Pilonidal cyst in infancy
Most reported literature of children with pilonidal cysts describes adolescents aged 15 to 17 years. There are few reports in the existing literature about infants with pilonidal cysts.
The specific etiology of a pilonidal sinus is unknown, but theories relate to formation along the gluteal fold at the time of embryogenesis as well as acquisition attributed to local soft tissue trauma.7 Embryologically, this mass may be related to separation of the remnants of the neural canal, failure of the 2 halves of the body to fully fuse at the midline,1 or remnant of the embryonic tail because of late regression.8,9 The literature seems to support that a congenital tract or cleft exists that creates a suction effect, drawing hair into this midline pit.10,11 This ingrown hair and blockage of the sinus tract causes a foreign body granuloma reaction,12 leading to inflammation, bacterial invasion, and infection.13 Skin flora organisms are most often the causative agent.7 A relationship may exist between sacrococcygeal dimples and pilonidal cysts, but this link is unknown.14 Pilonidal sinus is thought to be present in 15% of newborns and most commonly manifests as drainage into the superficial skin layers leading to a pilonidal cyst or abscess.1
Pilonidal cyst occurring during infancy was reported by Lewin15 in 1965 in a case report of a female infant who developed a red nodule at 3 days of life that grew in size over the next few days. This child was febrile to 104°F and wound cultures grew Staphylococcus aureus. At this time, 38 similar cases were reviewed from 1954 to 1963, with a large proportion present at birth, suggesting possible congenital origin of these pilonidal sinuses, some of which were associated with other congenital abnormalities. Acquisition secondary to trauma was another suggested mechanism.
Spinal dysraphisms have been found to occur in conjunction with cutaneous lesions (including hemangioma and sacral dimples), but rarely with pilonidal sinus. A case report of a tethered cord occurring with a laterally communicating pilonidal sinus was reported but had associated findings of enuresis and gross muscle wasting of lower extremities.1
Bacteremia and meningitis have been reported in relation to infected pilonidal sinus and therefore are important considerations in such cases. Anaerobes were the most commonly cultured organisms in a study of pediatric patients with pilonidal cyst abscesses, so empiric coverage should reflect this.16,17 Despite these occurrences, pilonidal cyst in infancy is rare and seldom documented in the literature. This becomes a concern in adolescence when hair growth and production of skin oil increase.18
The patient was admitted for further management of a pilonidal cyst. Vancomycin was continued. The wound became more fluctuant and incision and drainage was performed with return of 4 mL of frank pus. Wound culture grew S aureus, susceptible to vancomycin. Workup for chronic granulomatous disease by flow cytometry was initiated due to consideration of immunodeficiency status predisposing to abscess formation, and was found to be negative.
The child was discharged home on oral clindamycin for treatment of methicillin-resistant S aureus (MRSA) wound infection for a total of 14 days of antibiotic treatment following the finalization of wound cultures. Peripheral blood culture remained negative. The patient followed up with pediatric surgery outpatient for removal of packing.
Pilonidal cyst, although rare, can occur in young infants. The possibility of meningitis or spinal dysraphism still exists and should be considered in such cases. Antibiotics are likely indicated.
1. Shah A, Safaya A. Spina bifida manifesta: tethered cord syndrome with pilonidal sinus in a 4-month old baby. J Neuroradiol. 2013;40(3):221-223.
2. Sifuentes Saenz M, Meeks NJL, Tsai A, Elias ER. Genetics and dysmorphology. In: Hay WW Jr, Levin MJ, Deterding RR, Abzug MJ, eds. CURRENT Diagnosis and Treatment Pediatrics. 23rd ed. New York, NY: McGraw-Hill; 2016:ch 37.
3. Fetal imaging. In: Cunningham FG, Leveno KJ, Bloom SL, et al. eds. Williams Obstetrics. 24th ed. New York, NY: McGraw-Hill; 2014:ch 10.
4. Khoury C. Closed spinal dysraphism: clinical manifestations, diagnosis, and management. UpToDate. Available at: https://www.uptodate.com/contents/closed-spinal-dysraphism-clinical-mani.... Updated September 27, 2017. Accessed October 16, 2017.
5. Egler RA, Levin D, Wilkins-Haug L. Sacrococcygeal germ cell tumors. UpToDate. Available at: http://www.uptodate.com/contents/sacrococcygeal-germcell-tumors. Updated September 8. 2017. Accessed October 16, 2017.
6. Graham DK, Craddock JA, Quinones RR, et al. Neoplastic disease. In: Hay WW Jr, Levin MJ, Deterding RR, Abzug MJ, eds. CURRENT Diagnosis and Treatment Pediatrics. 23rd ed. New York, NY: McGraw-Hill; 2016:ch 31.
7. Burgess BE. Anorectal disorders. In: Tintinalli JE, Stapczynski JS, Ma OJ, Yealy D, Meckler GD, Cline DM, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill; 2016:545-562.
8. Efrat Z, Perri T, Meizner I, Chen R, Ben-Rafael Z, Dekel A. Early sonographic detection of a ‘human tail’: a case report. Ultrasound Obstet Gynecol. 2001;18(5):534-535.
9. Zimmer EZ, Bronshtein M. Early sonographic findings suggestive of the human fetal tail. Prenat Diagn. 1996;16(4):360-362.
10. The abdomen, perineum, anus, and rectosigmoid. In: LeBlond RF, Brown DD, Suneja M, Szot JF, eds. DeGowin’s Diagnostic Examination. 10th ed. New York, NY: McGraw-Hill; 2015:ch 9.
11. Bullard Dunn KM, Rothenberger DA. Colon, rectum, and anus. In: Brunicardi FC, Andersen DK, Billiar TR, et al, eds. Schwartz’s Principles of Surgery. 10th ed. New York, NY: McGraw-Hill; 2015:ch 29.
12. Kelly EW, Magilner D. Soft tissue infections. In: Tintinalli JE, Stapczynski JS, Ma OJ, Yealy D, Meckler GD, Cline DM, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill; 2016:1029-1038.
13. Aarons CB, Sentovich SM. Anorectum. In: Doherty GM. eds. CURRENT Diagnosis and Treatment: Surgery. 14th ed. New York, NY: McGraw-Hill; 2015:ch 31.
14. Block SL. The enigmatic sacro-coccygeal dimple: to ignore or explore? Pediatr Ann. 2014;43(3):95-100.
15. Lewin, RA. Pilonidal sinus in infancy. Pediatrics. 1965;35(5):795-797.
16. Brook, I. Anaerobic meningitis in an infant associated with pilonidal cyst abscess. Clin Neurol Neurosurg. 1985;87(2):131-132.
17. Brook I, Anderson KD, Controni G, Rodriguez WJ. Aerobic and anaerobic bacteriology of pilonidal cyst abscess in children. Am J Dis Child. 1980;134(7):679-680.
18. Stites T, Lund DP. Common anorectal problems. Semin Pediatr Surg. 2007;16(1):71-78.