Clinical • Concise report Clinical and Experimental Dermatology

Unexpected location of pilonidal sinuses

N. Sion-Vardy,*† L. Osyntsov,*† E. Cagnano,*† A. Osyntsov,‡† D. Vardy† and D. Benharroch*† *Department of Pathology, Soroka University Medical Center, Beer-Sheva, Israel; †Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; and ‡Department of B, Soroka University Medical Center, Beer-Sheva, Israel doi:10.1111/j.1365-2230.2009.03272.x

Summary Pilonidal sinuses usually occur in the sacrococcygeal area in young men, and occasionally can be found in other ectopic sites. We present a retrospective case review on unusual locations of pilonidal sinuses in the past 4 years. The lesion sites were as follows: one on the penis, two on the , two on the abdomen, one on the neck, two in the groin and two in the axilla. Abdominal and penile lesions are uncommon, but the other locations reported are unusually rare. To our knowledge, the groin has not been reported previously as a site of a pilonidal sinus, although the histological appearance of suppurativa may well resemble it. When trying to clarify the pathogenesis of these occurrences, we found that recurrent hair removal was a common characteristic of the patients we contacted, and this may have been the initiating trauma.

Pilonidal sinuses are found most often in the sacro- (EC). Genuine pilonidal sinuses or had to show one coccygeal area in young men. These cysts are consid- or both of the following histological features: sinuses ered to be a result of excessive and repetitive trauma. (sometimes with hair seen protruding from a small , cellulitis and fistulas, and on rare occasions opening), and a sinus tract that may extend from the squamous cell carcinoma may result. Pilonidal cysts opening and was lined by inflamed granulation tissue have occasionally been reported in other locations and (hairs located within the dermis or the subcutaneous area may also be related to repeated trauma.1 elicit a foreign-body reaction). A candidate case was Several such cases have been examined in our excluded if both hairs and sinus tracts with inflamed pathology department over the past 4 years. We granulation tissue were absent. describe the clinical and pathological features of piloni- In total, 10 cases (5 men, 5 women) of typical dal sinuses located at unusual sites and discuss the pilonidal sinuses at atypical body sites were accepted as possible diagnostic and pathogenic implications. genuine, and we were able to contact 6 of them. The characteristics of the patients and the sites are detailed in Table 1. Of the six patients we contacted, five Report reported regular hair removal in the relevant area; Over the past 4 years, unusual locations of pilonidal cysts three patients used a razor, one used an electric were noted by one of us (LO), hence we reviewed all razor, and the fifth (patient 10) used wax. Patient 7 pathology reports of pilonidal sinuses seen in our depart- reported a recurrence 15 months after the first occur- ment to identify additional cases with ectopic location. rence, which was not treated surgically. No recurrence The diagnosis was confirmed by our dermatopathologist was noted in the remaining cases. Pilonidal sinus has rarely been described in parts of the body other than the sacrococcygeal area and may Correspondence: Dr Daniel Benharroch, Department of Pathology, Soroka be confused with the diagnosis of hidradenitis suppura- University Medical Center, PO Box 151, Beer-Sheva 84101, Israel. tiva (HS) or dissecting cellulitis. HS was considered in E-mail: [email protected] the cases that had axillary and inguinal involvement. Conflict of interest: none declared. However, the lesions were not painful and were not Accepted for publication 22 October 2008 accompanied by a debilitating condition. They did not

Ó 2009 The Author(s) Journal compilation Ó 2009 British Association of Dermatologists • Clinical and Experimental Dermatology 1 Ectopic pilonidal sinuses • N. Sion-Vardy et al.

Table 1 Ectopic location of pilonidal sinuses: clinical features.

Age, Lesion Clinical Able to Removed Type of hair Patient Gender years site diagnosis contact hair? removal Recurrence Comments

1 M 41 Penis SC No – – – No actinomyces 2 M 27 Scalp SC No – – – – 3 M 25 Abdomen SC No – – – – 4 F 20 Scalp Yes No – No Granuloma 5 M 23 Neck SC Yes Yes Electric shaver No – 6 F 28 Groin HS No – – – – 7 M 19 Axilla SC Yes Yes Razor Yes – 8 F 32 Suprapubic Yes Yes Razor No – 9 F 22 Axilla LN Yes Yes Razor No – 10 F 28 Groin SC Yes Yes Wax No –

HS, ; LN, lymph node; SC, sebaceous cyst. lead to psychological problems and recurrence was seen Axillary pilonidal sinuses are also very rare.11 Previ- only with one axillary lesion.2–4 Hair was always ously reported cases were non-hirsute healthy women, present within the lesions, and therefore we believe aged 17–30 years. The lesion has been attributed to that the axillary and inguinal cases were indeed cases of friction or suction, due to movements of the . Other pilonidal sinus. Histology compatible with is factors mentioned are shaving, minor infections and usually the case with HS rather than appocrinitis, in maceration. Both patients gave a history of axillary which it is uncommon.5 We believe that in some cases, shaving. a pilonidal sinus is part of the pathology of HS. Abdominal pilonidal sinus has been previously We considered the diagnosis of dissecting cellulitis in reported at an umbilical or peri umbilical location only. two of our cases involving the scalp. However, pain was At this site, this condition involves predominantly not a feature in our patients, and the condition did not young men with abundant body hair, a deep navel present as pustular nodules, showed no progression and and poor personal hygiene.12 Our two patients had did not recur to result in scarring alopecia.6,7 The two abdominal pilonidal sinuses unrelated to the umbilicus. cases involving the scalp are therefore most consistent The 32-year-old woman presented a ‘suprapubic with pilonidal sinuses. abscess’, and she had shaved this area. The second Penile pilonidal sinus, as seen in our first case, is rare patient was a young man with a lower abdominal and most often situated in the foreskin.8 It has been midline lesion. suggested that the penile coronal sulcus represents a The trauma of shaving probably underlies the devel- cleft in which hair accumulates and may form a opment of pilonidal sinus in most of our cases. To our pilonidal sinus.9 In our case, the pilonidal sinus was knowledge, only one patient of the six with a follow-up situated in the mid shaft of the penis. The patient was had a recurrence after the surgical excision. Assuming circumcised and developed a pilonidal sinus at a penile that the pathogenic mechanisms are similar in sacro- site, which has not previously been described. No coccygeal and ectopic pilonidal disease, the recurrence evidence of actinomyces was found. of one lesion is not surprising. Pilonidal sinus of the scalp is rare. One of our two The histological features of pilonidal sinus may be patients with pilonidal sinus at this site was a young found in cutaneous lesions that are not considered Ethiopian man and the sinus was associated with clinically as the ‘typical sacrococcygeal’ pilonidal sinus repeated shaving of his hair. In the second patient, the and should be considered in the diagnosis of such cyst seemed to adhere to the temporal fascia and lesions. Local repeated minor trauma to hairy areas is showed a marked granulomatous reaction. Pseudo- probably the main pathogenic mechanism. folliculitis is a common problem seen in shaved areas of curly hair and may result in a pilonidal sinus.10 References Pilonidal sinuses of the groin have not been previ- ously recorded, to our knowledge. The clinical diagnosis 1 Ballas K, Psarras K, Rafailidis S et al. Interdigital piloni- was HS in one of our patients and a sebaceous cyst in dal sinus in a hairdresser. J Hand Surg [Br] 2006; 31: the other. Hair removal by waxing or shaving may 290–1. result in pseudofolliculitis. Similar histology has been 2 Shah N. Hidradinitis suppurativa: a treatment challenge. described in cases of HS.5 Am Fam Physician 2005; 72: 1547–52.

Ó 2009 The Author(s) 2 Journal compilation Ó 2009 British Association of Dermatologists • Clinical and Experimental Dermatology Ectopic pilonidal sinuses • N. Sion-Vardy et al.

3 Cusack C, Buckley C. Entanercept. Effective in the man- 8 Rao AR, Sharma M, Thyveetil M et al. Penis: an unusual agement of hidradenitis suppurativa. Br J Dermatol 2006; site for pilonidal sinus. Int Urol Nephrol 2006; 38: 154: 726–9. 607–8. 4 Mendoca CO, Griffiths CE. Clindamycin and rifampicin 9 Val-Bernal JF, Azcarretazabal T, Garijo MF. Pilonidal combination therapy for hidradenitis suppurativa. Br J sinus of the penis. A report of two cases, one of them Dermatol 2006; 154: 977–9. associated with actinomycosis. J Cutan Pathol 1999; 26: 5 Jemec GB, Thomsen BM, Hansen U. The homogeneity 155–8. of hidradenitis suppurativa lesions. A histological study 10 Kelly AP. Pseudofolliculitis barbae and keloidalis of intra-individual variation. APMIS 1997; 105: 378–83. nuchae. Dermatol Clin 2003; 21: 645–53. 6 Krasner BD, Hamzavi FH, Murakawa GJ et al. Dissecting 11 Ohtsuka H, Arashiro K, Watanebe T. Pilonidal sinus of the cellulitis treated with the long-pulse Nd: YAG Laser. axilla: report of five patients and review of the literature. Dermatol Surg 2006; 32: 1039–44. Ann Plast Surg 1994; 33: 322–5. 7 Chinnaiyan P, Tena LB, Brenner MJ et al. Modern external 12 Eryilmaz R, Sahin M, Okan I et al. Umbilical pilonidal sinus beam radiation therapy for refractory dissecting cellulitis of disease. Predisposing factors and treatment. World J Surg the scalp. Br J Dermatol 2005; 152: 777–9. 2005; 29: 1158–60.

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