Umbilical Pilonidal Sinus

Introduction

There are approximately 70,000 cases of pilonidal disease (PD) each year in the United States. These lesions commonly present in adolescence, but may occur throughout the post puberty years¹.

PD can be extremely uncomfortable and cause significant distress and embarrassment to patients. PD is thought to be the result of a foreign body reaction, most commonly body hair, that becomes impacted in a sub-cutaneous cavity causing a granulomatous reaction and chronic inflammation over time ². This disease, well-known to general surgeons and plastic surgeons, was described by Mayo in 1833 as a hair containing cyst located just below the coccyx. While most PD is formed just below the coccyx, there have been several documented cases of pilonidal sinuses occurring in other parts of the body ³.

Umbilical pilonidal sinuses (UPS) have historically been more difficult to treat as there is no established treatment algorithm. The existing literature regarding the management of UPS states relatively similar outcomes between conservative management with hair extraction and surgical intervention. We present an unusual case of an UPS in a teenage girl who has had recurrent episodes of purulent discharge from the umbilicus and was operated as conservative treatments failed.

Case presentation

A 15-years old girl presented with painful, swollen umbilicus and purulent discharge in October, 2023. She gave the history of acute pain around the umbilicus two weeks ago and has had consultation with a general surgeon in a private clinic. Investigations were done with the provisional diagnosis of acute appendicitis. The laboratory results and ultrasound examination of abdomen and pelvis was not in favor of appendicitis and neither of pelvic pathology. She was kept under observation and treated conservatively for the acute inflammatory condition of uncertain origin. A few days during the observation period, pus discharge was noticed from the umbilicus. Patient’s parents requested discharge from the hospital and attended the follow-up clinic. As the umbilicus continues to discharge purulent exudates ad umbilical pain persists, she was referred to us.

On first visit to us, she has had acute inflammation around the umbilicus and thorough local examination could not be done, because of excruciating pain and tenderness. Pus for culture and sensitivity was sent and wound care continued, while waiting for the result. Pus for culture was reported as no growth, so 3rd generation cephalosporin has to be continued and Metronidazole was added for anaerobic cover.

Fortunately, the acute inflammation partially settle down, allowing proper examination of the umbilicus. Granulation tissue was detected deep inside the umbilicus and a tract could be felt on gentle probing, giving the opportunity to attempt sinogram X-ray. The sinogram shows a blind tract ending in the muscle layers of the abdominal wall.

Fig 1. Sinogram (AP view) Sinogram (lateral view)

Elective surgical procedure was planned after the inflammation was completely subsided. Counselling for sinus exploration was done with her parents, in term of possible laparotomy if the sinus tract was found out to have communication with intra-abdominal organs (small bowel, if it turned out to be patent Vitallo-intestinal duct; bladder if it were urachus).

Surgical Procedure in-brief

Modified para-umbilical incision was made to explore the sinus. Methylene blue dye was injected into the sinus to visualise the tract during the procedure.

The blue dye staining the sinus tract facilitates the surgical procedure. The tract passed through the rectus sheath and found to end before reaching the peritoneum.

There was no communication with intra-peritoneal structures (figures). The whole sinus tract was dissected out, leaving the umbilicus intact. The whole procedure takes less than an hour. The surgical specimen was sent for histological examination.

Histology reported as tract lined by granulation around hair follicles. No histological features of small bowel. No uro-thelial lining cells seen.

Discussion

Pilonidal sinus disease is a common surgical disorder. In 1833, Herbert Mayo first coined the term, pilonidal. The word “Pilonidal” means “nest of hair” and includes the etymological roots of pilus (hair) and nidus (nest). The disease generally occurs in the sacrococcygeal region but has also been reported in other locations in which an anatomical cleft facilitates an accumulation of hair including the axilla, perineum, penile shaft, in spaces between the fingers, and umbilicus. A negative pressure is created during body movements at the above mentioned sites, leading to penetration of the hair shafts into the skin with a resultant foreign body reaction and development of a sinus lined by granulation tissue. An umbilical pilonidal sinus is the rarest variant accounting for up to 0.6% of cases ⁴. The first case of an umbilical pilonidal sinus was reported in 1956 by Patey and Williams ³, and since then, only a few hundred cases have been reported in medical literature.

The clinical features of an umbilical pilonidal sinus result from inflammation in the sinus. Pain and swelling as well as purulent discharge are the usual symptoms are the usual symptoms. The predisposing factors being hairiness, male gender, a young age, a deep navel, and poor personal hygiene ^{1, 5}.

The differential diagnosis includes umbilical hernia, endometriosis, pyogenic granuloma, urachal cyst, epidermoid cyst, and Sister Mary Joseph nodule ^{5, 7}.

Although a diagnosis is made clinically by the detection of hair nests, pre-operative intra-abdominal imaging may be required for questionable cases.

Conservative treatment in the form of hair extraction on an out-patient basis, improved umbilical hygiene, and instructions on preventive measures can be used as first-line therapy for the management of an umbilical pilonidal sinus ⁸. Incomplete extraction of the hair from the sinuses is the main cause of failure with conservative treatment ^8-10.

First case of a UPS was reported in 1956 and fewer than 300 have been reported since its initial discovery, although uncommonly in children ⁹.

The umbilicus which embryologically serves as a point of entry and exit for multiple vital organ systems in the foetus, is an essential structure. However, its high traffic nature makes the umbilicus, vulnerable to a number of lesions including umbilical hernia, urachal cyst, Meckel’s diverticulum, umbilical granuloma, as well as lesser-known entities, such as UPS.

Disorders of the umbilicus in children are relatively common. Umbilical granuloma is a common lesion of the umbilicus in the paediatric population, which resembles the UPS. Granulomas most commonly form, following the severance of the umbilical cord, affecting up to 1 in 500 paediatric patients ¹⁰. Umbilical granulomas are usually treated with application of silver nitrate and do not require surgical intervention, if they are smaller than 1cm. Another common lesion to consider in the differential diagnosis is the persistent omphalo-mesenteric duct (a remnant communicating the ileum and the umbilicus). This condition is seen in two percent of the population and is usually treated with surgical excision. ¹¹

The discharge that accompanies persistent Omphalo-mesenteric duct can make its presentation similar to UPS. Urachal remnant (Urachus) can mimic UPS and occurs in about 1 in 5000 births. This condition usually present with urinary discharge and eventually require surgical excision ¹².

The root cause of UPS is the foreign body reaction, most commonly being hair. After the foreign body is introduced to the umbilical pit, increasing friction causes progressive inflammation and oedema. As a result of these inflammatory changes, the foreign body becomes trapped, ultimately resulting in sinus.

The most robust evidence available in the literature is a double blind, prospective, randomized, clinical trial in which non-operative management and surgical excision of the umbilical pilonidal sinus tract are compared. 84 patients diagnosed with UPS were enrolled and were randomized for non-operative management or surgical treatment. Patients were followed up for two years. Surgical excision of the tract was completed via a circular incision, which cored out the bottom 2/3 of the umbilicus. The tissue edges were approximated via sutures in the sub-cutaneous tissue, however, the skin was left open to allow the wound to drain. Non-operative management involved removing the hair without an incision followed by daily cleanser and proper wound care, (Kaplan et al.) ⁴ The author concluded that surgical intervention statistically and significantly results in shorter healing times as well as better cosmesis, when compared to non-operative management two years after initial presentation.

Conservative management also resulted in a higher recurrence rate, curing only 28 out of 41 patients, included in the non-operative management group, while surgery was the curative treatment for 100% of the patients in the surgical treatment group.

Occasionally, an incision and drainage of an abscess may be necessary 5. For cases that are resistant to conservative treatment with reconstruction of the umbilicus ¹¹.

Some surgeons have recommended umbilical excision and wound closure by secondary intention and found the subsequent scar to resemble normal depressed umbilicus ¹².

In our case, modification of peri-umbilical incision has been made and tried to preserve the umbilicus intact has been attempted. Successful result of our procedure has been shown in figure.

Conclusion

This is a report of an umbilical sinus, that was treated by surgical excision, preserving the umbilicus. Conservative treatment of the discharging umbilical sinus, failed repeatedly leading to repeated relapse and causing a high morbidity and prolonged hospital stay.

References

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Author Information

Win Myint¹, Aung Moe Hlaing²
1. Professor, Dagon Medicare Hospital
2. Senior Consultant, Dagon Medicare Hospital