A Curious Case of Recurrent Umbilical Swelling : Case Report and Literature Review

Background: Umbilical endometriosis, a rare benign condition, is clinically difficult to differentiate from other diseases that result in the formation of an umbilical nodule. It is caused by the presence of ectopic endometrial tissue in the umbilicus, which overtly presents as a painful, discoloured swelling in the umbilicus. However, in our case the presentation wasn’t as obvious. The endometrial tissue was embedded within an umbilical hernia. Case Summary: Our patient was a 37-year-old female with a past medical/surgical history of a subtotal colectomy for ulcerative colitis in 2001 followed by an ileo-rectal anastomosis. 17 years later, she was referred to the surgical outpatient clinic from GP practice with a painful umbilical/incisional hernia surrounding the previous scar and just above the umbilicus, this pain, particularly worsening during her menstrual cycle. Multiple blood tests and ultrasound scans of her abdomen failed to diagnose a cause for her agony which mandated an elective excision of the swelling. This successfully resolved her symptoms. Conclusion: Umbilical endometriosis is a potential diagnosis in females with a painful umbilical swelling, imaging has no diagnostic role and excision is the definitive treatment.


Introduction
Endometriosis is defined as the presence of endometrial glands and stroma outside the uterus affecting 3% to 10% of women in the reproductive age.However, endometriosis of the umbilical region is infrequent and when present in an umbilical hernia, it is exceptionally precocious.This has been noted to occur only in 0.5% -1% of all patients with endometrial ectopia-the first description of which is credited to Villar in 1886, hence the term "Villar's nodule".
We present a case of recurrent umbilical swelling, simple enough to be easily dismissed but complex enough to contain endometrial tissue and confuse with a sister josephs nodule.Especially that the clinical presentation was not as typical as expected.

Case Presentation
A 37-year-old Caucasian woman was referred from GP practice with a painful incisional hernia surrounding a previous scar; the pain particularly worsening during her menstrual cycle and associated with enlarging in size of the hernia.
Known to have IBD, she had previously had a subtotal colectomy for ulcerative colitis in 2001 followed by an ileo-rectal anastomosis which she was managing well.
Shortly after, she unfortunately developed an umbilical hernia at the caudal end of her midline scar associated with cyclical swelling and severe peri-umbilical pain.After being thoroughly investigated at her GP practice in terms of, blood tests and ultrasound scans-all of which revealed no abnormalities, she was referred to the surgical team for further evaluation as she was not tolerating the pain.During her consultation at our outpatient clinic she described a peri-umbilical sinus which has spontaneously healed a few years ago.
She was otherwise fit and well, not on any medications and declared no known drug allergies.
On examination she was clinically well, abdominal palpation not only revealed a tiny supra-umbilical hernia but also a healed periumbilical stitch granuloma measuring approximately 1 cm in diameter.
A repeat set of blood tests were sent off to the lab, all parameters were reported to be well within normal range (including inflammatory markers).Thereafter, an ultrasound scan was organized which revealed a hypodense nodule correlating with the stitch.
After obtaining informed consent she underwent an elective incisional hernia repair with the excision of the umbilical stitch granuloma.
A midline incision was made through the existing scar-a tiny caudal defect was identified measuring 0.5 cm, the hernia sac was reduced and defect closed.A hard umbilical lesion was also located, mobilized and excised en-bloc with skin.
The operation itself was uneventful.The wound was then closed in layers and the biopsy sent for histological reporting.On slicing of the lesion, the pathologist found it to be of a cystic consistency and identified benign endometrial glands, stroma, hemosiderin deposits and fibrosis were present (Figure 1 and Figure 2)-all in keeping with endometriosis.Luckily no atypical features were recognized.

Final Diagnosis
Umbilical endometriosis secondary to an umbilical hernia.
No further treatment was required after excision and repair of the lesion.

Outcome and Follow-Up
The patient was seen in clinic 6 weeks later and reported feeling much better after the operation.She remained asymptomatic, there was no evidence of clinical recurrence and thereafter, was discharged from surgical care.

Discussion
Endometriosis is a benign inflammatory disease characterized by the presence of estrogen dependent extra-uterine endometrial glands effecting 10% at the reproductive age of the women.It presents with a conglomerate of symptoms like turbulence of hormonal imbalances, chronic pain and infertility.parts of the gastrointestinal tract and the peritoneal surfaces [1] with more than 80% of the endometriosis cases primarily involve the ovaries followed the appendix, intestine, cervix, omentum, and skin [2].
The majority of cutaneous endometriosis occur secondary to abdominopelvic surgery.Spontaneously, cutaneous endometriosis commonly happens in the umbilicus, followed by the inguinal region and rarely the lateral abdominal wall could be involved [3].
Umbilical endometriosis is further classified as primary if it occurs spontaneously or secondary if it results from iatrogenically-seeded endometrial implants following various surgical procedures, with the latter being more common [4] [5].
The pathogenesis of primary umbilical endometriosis remains unclear.Possible theories for this disorder could be the migration of endometrial cells to the umbilicus through the abdominal cavity, the lymphatic system, or through the embryonic remnants in the umbilical fold such as the urachus and the umbilical vessels, genetic predisposition, and immunological defects [6].
On the other hand, development of secondary umbilical endometriosis usually follows laparoscopic surgical procedures involving the umbilicus [7].This occurs through the dissemination of endometrial implants to the umbilical region and other areas which may occur in a surgical setting where direct exposure of endometrial tissue occurs to tissue tracts and blood vessels exposed by mechanical disruption.The fibrin-rich surfaces of incisions provide viable sites for deposition of angiogenic endometrial implants [8].
In this case, the patient's surgical history of a midline scar was consistent with secondary umbilical endometriosis.Extra-pelvic endometriosis is difficult to diagnose due to the extreme variability in presentation.Umbilical endometriosis usually manifests as a nodule of variable size.A characteristic sign for this lesion is the simultaneous sanguinolent discharges with menstruation.Clinical symptoms typically include pain, bleeding, and swelling concurrently with menstruation, however others are asymptomatic [9] [10].The presence of a previous history of endometriosis is common (26% of cases) [11], frequently associated with complaints of dysmenorrhoea, dyspareunia, or defecation pain [2].
Non-invasive tests for endometriosis such as CT, MRI, ultrasonography, and serum carbohydrate antigen 125 levels are all commonly used, but the results of these screening procedures are inconclusive [3].
In umbilical endometriosis specificlly, both CT scan and MRI generally demonstrate a solid well-circumscribed mass, define the size and locations of the lesions and exclude the possibility of intraabdominal extension [8] [12] [13] [14].But, more often than not, definitive diagnosis is only confirmed by visual inspection via laparotomy or laparoscopy [3] or histopathology following surgical exploration and excision of the underlying lesion.
As a result, multiple studies have reported a delay in the diagnosis of endometriosis [15].
Luckily, several symptoms can be predictive of endometriosis such as severe dysmenorrhoea in infertile women, abdominopelvic pain, dysmenorrhoea, heavy menstrual bleeding, infertility, dyspareunia, postcoital bleeding and/or previous diagnosis of ovarian cyst, irritable bowel syndrome, or pelvic inflammatory disease [16] and these symptoms and signs can help us to consider the diagnosis of endometriosis when an umbilical nodule is present.
Once diagnosed, endometriosis is quite challenging to manage given both it's unknown cause and tendency to progress and recur despite treatment.
The best approach in these situations is the total removal of the umbilicus with an adequate rim of normal tissue around [17] as the medical treatment of umbilical endometriosis, based on hormonal therapy (norethisterone, progesterone, danazole, gonadotropin-releasing hormone analogue) often fails to control the disease [18] [19].
The histological features required for the diagnosis of endometriosis are the concomitant presence of two of the three following characteristics: endometrial-like glands, endometrial stroma, or hemosiderin pigment [20].
Other causes of umbilical nodules range from benign ones such as, cutaneous endometriosis/endosalpingosis, haemangioma/vascular malformation, umbilical hernia, sebaceous cyst, lipoma, granuloma (which was an initial first suspect in our case), abscess and keloids, to malignant pathologies like sister joseph nodes, sarcoma, lymphoma and melanomas.
Umbilical endometriosis in particular is of interest to the general surgeon as it may be mistaken for a suture granuloma (as above), melanoma, cyst, abscess or a metastatic deposit from a systemic malignancy [21].

Conclusions
Surgical site associated umbilical endometriosis is a relatively rare form of endometriosis, which leads to delayed presentation to the surgeons after all investigations fail to diagnose a disease.
The suspicion of the diagnosis of umbilical endometriosis is based on the clinical presentation, but the definitive diagnosis should always be confirmed by histological examination following biopsy or resection.

Figure 1 .
Figure 1.Histological images of the excised umbilical lesion ×2 low power magnification showing epidermis on the left upper part, dermis with endometrial glands and stroma towards the right.

Figure 2 .
Figure 2. Histological images of the excised umbilical lesion ×10 magnification showing benign endometrial glands and stroma.