Scar endometriosis diagnosed as incisional hernia before surgery

Abstract

Scar endometriosis is a rare condition highly related to history of abdominal surgery. Due to the low incidence, it is often misdiagnosed. A woman presented to the surgery outpatient clinic with a mass near her C-section scar. Physical examination and ultrasound suggested Incisional Hernia while intraoperative finding revealed a mass suggestive of endometriosis which later confirmed by pathology examination. Scar endometriosis is a common subtype of extra-pelvic endometriosis. Iatrogenic transplantation is speculated to be its etiopathogenesis. Preoperatively, it is challenging to differentiate endometriosis from another abdominal masses. The definitive diagnosis is based on laparoscopy or surgery with histological verification. Chronic pain is complex and often involves multiple factors beyond simply a diagnosis of endometriosis, but it is important to think of endometriosis on women patients presenting with a mass and cyclic pain with history of surgery involving a large amount of endometrial cell.

Background

Endometriosis is diagnosed by the presence of viable, oestrogen-sensitive endometrial-like glands and stroma outside the uterus on pathological examination.¹ When endometriosis presents on a caesarean section scar, it is diagnosed as abdominal wall endometriosis, scar endometriosis or surgical scar endometriosis.² Scar endometriosis is a rare condition which highly related to a history of abdominal surgery. Although rare, scar endometriosis is the most common site for extra-pelvic endometriosis.³ Endometriosis affects 6%–10% of women of reproductive age with abdominal endometriosis itself accounts for only 1.04% of endometriosis.^{4 5} Due to the low incidence, it is often misdiagnosed as incisional hernia, granuloma or abdominal wall tumour.⁵ Therefore, it is necessary to share this diagnosis of endometriosis outside the field of obstetrics and gynaecology because other surgeons might not have encountered the cases.⁴ Typical patients with scar endometriosis present with a triad consisting of a history of caesarean delivery or other abdomino-pelvic surgery, cyclic pain associated with menses and mass near the surgical scar.⁶ This is a case report of intraoperative findings of endometriosis lesions which was diagnosed as an incisional hernia before surgery.

Case presentation

A 41-year-old woman presented to the surgery outpatient clinic with a mass on the left superior aspect of her C-section pfannenstiel scar. She had caesarean section 13 years ago due to breech presentation. She noticed the mass 2 years ago as she could feel a bulge when palpating her abdomen. She ignored the mass because it did not cause her any significant pain. Two months before her admission, she was experiencing pain around the mass area which worsens during her menstruation cycle. The pain was significant enough to cause her to go see a surgeon. On physical examination, there was palpable, soft, subcutaneous mass sized 5×6 cm on the left superior aspect of her pfannenstiel scar. The mass was irreducible but no incarceration suspected as the pain felt was not acute or severe and bowel movement was still present. Incisional hernia was suspected and she was sent to radiology unit to confirm the diagnosis by sonography.

Investigations

Ultrasound (US) examination was performed and it showed a hypoechoic inhomogeneous lesion with relatively fine margin but slightly jagged edges sized 1.8×1.7 cm on the left lower quadrant of her abdominal wall, Doppler showed no vascularisation. An anechoic lesion with fine margin sized 1.6×1.3 on her right adnexa was also found. The US examination concludes of soft tissue tumour on the left lower quadrant of the abdominal wall suggestive of incisional hernia and a right ovarian cyst. An advanced imaging such as CT-scan or MRI was not performed because it was not available at our hospital. The general surgeon planned to repair the incisional hernia but consulted to an OB/GYN first for her ovarian cyst. The patient was advised to come back 6 months later by the OB/GYN for her cyst observation and the general surgeon was allowed to proceed the initial surgery plan. The surgery was performed, an incision was made on top of the mass. Durante incision, a brownish-black lobulated mass was seen. The surgeon decided to make an ellipse incision with a margin about 1.5 cm around the mass (figure 1A). A mass sized 4×5 cm was excised until the base of subcutaneous layer (figure 1B). The lobulated, capsulated, brownish-black mass were a little fragile and fragmented during excision (figure 2). All mass was taken out during the surgery. It was then diagnosed as lesion suggestive of endometriosis and a biopsy sample was sent to referring hospital for anatomical pathology examination.

Figure 1.

(A) The irreducible subcutaneous mass on the left superior aspect of pfannenstiel scar and marker for incision; (B) after the excision of the mass.

Figure 2.

Brownish-black lesion suggestive of endometriosis (in green circles).

Outcome and follow-up

The patient came for a postoperative follow-up 1 week after her surgery. There is no sign of wound infection on the surgical site. The pathological result was also obtained on her appointment with a result showing fibro-collagen stroma and mature fat tissue with endometrial structure. Endometrial structure was consisted of dense stroma and endometrial gland with a tubular shape, some dilated in a cystic manner, layered by hyperplastic thoracal epithelial cells. Nuclei were within normal limit. There was also macrophage consisted of hemosiderin pigment. No malignancy tumour cell was found. The pathological examination results in endometriosis externa (figure 3). She reported of pain around her surgical site wound but said to be gone with analgesia. On her second appointment 1 week later, she admitted to having less pain on her last menstrual period. She was then referred to the OB/GYN in another facility with more advanced care.

Figure 3.

Pathological examination showing endometrial foci (left: ×20 magnification, right: ×40 magnification).

Discussion

Endometriosis is a condition characterised by the presence of uterine mucosal tissue outside the uterus. It affects 6%–10% of women of reproductive age being usually located in the pelvis. Extra-pelvic endometriosis is rare but was reported in a wide range of sites such as lung, liver, gallbladder, gastrointestinal tract, perineum, central nervous system, umbilicus, inguinal hernias or the abdominal wall.^{2 4} Scar endometriosis is a common subtype of extra-pelvic endometriosis but it only accounts for 1.04% of endometriosis and found in 1%–2% of women following caesarean section.^{2 5} Obstetric surgery remains an important risk factor since it can expose a large amount of endometrial cells and these cells can be entrapped in the wound.⁶ Although caesarean delivery and abdominal hysterectomy scars are the most common predisposing factors, scar endometriosis has also been reported in laparoscopic trocar tracts or amniocentesis needle tracts and even on non-gynaecological surgeries as those from appendectomies or umbilical hernioplasties.^{4 7} The theory of direct implantation is widely accepted by many authors while others agree endometriotic node occurs because of scar tissue metaplasia, and some support the migration theory through lymphatic or vascular vessels.⁷ To conclude, the disease’s etio-pathogenesis remains a mystery. Perhaps to prevent iatrogenic transplantation, additional attention is needed during surgery that exposes endometrial tissue.⁶ Even though the endometrium is found in areas outside its normal localisation, endometriotic foci still contain normal endometrial tissue and for this reason, they perform a menstrual cycle as an organ functioning within itself.⁸ The human endometrium is hormone-dependent and undergoes cyclical hyperplasia, secretion and shedding. The ectopic endometrial foci in endometriosis respond to cyclical hormonal changes in the same way as the intrauterine endometrium which results in focal bleeding, inflammation and fibrosis. This manifests in symptoms which vary in frequency and intensity, including dysmenorrhoea, menorrhagia, dyspareunia and pelvic pain.⁹ During menstrual periods, thickening, destruction and menstrual bleeding also occur almost always in these areas, just as in the endometrium.⁸ Most patients with scar endometriosis present with a mass and pain. However, endometriosis may present with acute abdominal symptoms mimicking hernia.² It is important to elicit a thorough history from the patient, specifically inquiring about the occurrence of pain, whether it is cyclic and worse during her menstrual cycles.¹⁰ The great variability in the clinical presentation and limited knowledge of the disease cause difficulty in diagnosing endometriotic nodes in scars, especially among specialists who do not normally treat this type of patient.⁷ Even to OB/GYN, endometriosis presents significant challenges in terms of diagnosis and management. Despite decades of research, there are no sufficiently sensitive and specific signs and symptoms nor blood tests for the clinical confirmation of endometriosis.¹¹ Preoperatively, it is challenging to differentiate endometriosis from another abdominal masses with diagnostic rate ranging from 20% to 50%.² Imaging is often used in the investigation of chronic pelvic pain but its predictive value depends on the experience of the centre performing the ultrasonography and is very highly operator-dependent.¹ Lesion may appear as a hypoechoic nodule with spiculated margins that infiltrate the surrounding tissue, and the use of power Doppler enables us to see a poor and heterogenous peripheral vascularisation.¹² In regard to its low incidence, small centres not exposed to a lot of such cases makes ultrasonography not as sufficient. Meanwhile in experienced centres, the sensitivity and specificity of finding the disease is much higher even though it is limited to certain type of endometrial lesions, such as deeply infiltrating endometriosis or endometrioma.¹ Although the definitive diagnosis is based on laparoscopy or surgery with histological verification of endometrial glands and/or stroma, imaging is necessary for treatment planning. Among imaging modalities, MRI is often used as a problem-solving additional examination in complex cases and should be considered as a second-line technique after US. Currently, MRI is considered the best imaging technique for mapping endometriosis, since it provides a more reliable map of deep infiltrating endometriosis than physical examination and transvaginal US. The MRI appearance of endometriotic lesions is variable and depends on the quantity and age of haemorrhage, the amount of endometrial cells, stroma, smooth muscle proliferation and fibrosis.¹³ As CT of the pelvis does not visualise pelvic organs well, it is not useful in the diagnosis of endometriosis. An important role for the CT scan with contrast is to detect ureteral involvement and possible renal insufficiency.¹⁴ The differential diagnosis is very wide, especially in umbilical endometriosis. All types of possible tumours should be considered, whether primary or secondary, benign or malignant. The main conditions to take into account are hernias, lipomas, haematomas, abscesses, anomalies of the urachus and the omphalomesenteric duct, melanomas and keloids.¹² Endometriosis can also be easily mistaken for incarcerated preperitoneal fat and any suspicion should prompt a resection and pathological examination.¹⁰ Complete wide excision is both diagnostic and therapeutic. Although benign in structure, endometriosis has all the features of malignancy, such as local spread, invasiveness and an outstanding ability to disseminate.⁶ So the aim of radical surgical treatment despite preventing local recurrence, is to enable accurate pathological diagnosis and prevent the malignant transformation of the residual tissue.¹⁵ Currently, several therapeutic options both hormonal and non-hormonal are available to provide symptomatic relief and control the progression of the disease. Several hormonal therapies which can be used are combined oral contraceptives, progesterone containing contraceptives (oral/injectable, implant, Levonorgestrel-releasing intrauterine system (LNG-IUS)), selective progesterone modulator (mifepristone, ulipristal acetate, onapristone), gonadotrophin releasing hormone agonist (leuprolide acetate, nafarelin, goserelin) and antagonist (cetrorelix). Aside from hormonal therapies, there is also non-hormonal options such as Nonsteroidal anti-inflammatory drugs (NSAIDs), aromatase inhibitor and danazol. All the options discussed above have been equitably successful in controlling pelvic pain in women with endometriosis. In carefully selected women these medications can be used either alone or in combination with surgery. However, they (except NSAIDs) are limited by their side effects and negative impact on fertility.¹⁶

Patient’s perspective.

Ï first noticed I had a lump near my caesarean scar 2 years ago when I was rubbing my stomach. I was not too worried because it was not painful and I could still do my daily activities. Around 2 months before my visit to the surgery clinic, I felt pain around the area of the lump. The pain was disturbing enough to make me want to see a surgeon. The surgeon told me the tumour was most likely to be benign and offered me option to remove it. I wanted it to be removed as I felt so uncomfortable by its presence.

The surgeon asked me to go to radiology unit for abdominal sonography. Once I finished, I went back to the surgery clinic with my result. The general surgeon told me that I have an abdominal mass that’s most likely to be an incisional hernia and I also have a right ovarian cyst. The general surgeon gave me a consult referral request and asked me to go to the OB/GYN clinic tomorrow.

When I went to see the OB/GYN, he told me it was only a small ovarian cyst and a surgery was not necessary. He just wanted to observe it so he asked me to come back 6 months later for a follow-up. He told me I could go along with the general surgeon plan to remove the abdominal tumour.

So the surgeon arranged an elective surgery schedule to remove the tumour. When I was admitted to surgery ward before my procedure, the general practitioner asked me a few questions and one of them was if I experienced worsening of pain during my menstrual period. I was not aware of it but since the doctor mentioned it, I realised my pain was cyclic. The general practitioner reported it to the general surgeon and informed me that they had suspicion of a rare form of endometriosis but we will know for sure once they open me up.

Few hours later during my surgery, the general surgeon asked me if I had any abdominal surgeries before. I mentioned my C-section 13 years ago. The general surgeon informed me that they would send some samples from the tumour for biopsy and the result should be available next week.

The following week, I went to see the general surgeon for a post-op wound care and he informed me my biopsy results in endometriosis externa. He then explained to me that it’s very rare and he would refer me to an OB/GYN in a more advanced facility after my second post-op appointment.

On my second post-op appointment, I was asked to see the general practitioner who examined me when I was first admitted to the surgery ward. The general practitioner educated me about endometriosis and how in most cases, it could compromise women’s fertility. I was so grateful that I already had a child before I was diagnosed with the disease. She also asked me if my menstrual pain was getting better and I told her yes. She then explained to me that recurrence could happen and that I should see an OB/GYN to control the disease.

Learning points.

• Scar endometriosis is a rare case but the most common of extra-pelvic endometriosis.

• Scar endometriosis is the great imitator of abdominal masses.

• Cyclic pain with history of abdomino-pelvic surgery was the key finding of ectopic endometriosis, in particular in this report was scar endometriosis of caesarean scar.

• The mass of endometriosis should be taken out completely.