Abstract: Scar endometriosis is an infrequent type of extra pelvic endometriosis that is rather close together with obstetrical and gynaecological surgeries. Scar endometriosis is reported in only 0.03-0.15% of all cases of endometriosis. We are reporting a case of 39 years old female patient presenting with scar endometriosis 10 years after her last lower segment caesarean section. The patient came to the Gynaec OPD, NIUM Hospital on 6^th May 2019 with the compliant of supra pubic swelling since 6 months, which was growing slowly. Her menstrual history was regular, but she had lower abdominal pain during menstruation. Patient had two children delivered by LSCS. On clinical history, examination, USG and FNAC finding the swelling was diagnosed as scar endometriosis.

Key words: Endometriosis, Abdominal scar, LSCS and Prevention

Introduction: Endometriosis is defined as the presence of endometrial glands and stroma outside the uterus. It affects 10-15% of all women of reproductive age i.e. 18-45 years ^{(1, 2)} and 70% of women had chronic pelvic pain. ⁽³⁾ Endometriosis occurs in abdominal, extra abdominal and remote areas. Scar endometriosis is reported in only 0.03-0.15% of all cases of endometriosis. Several reproductive factors have been consistently associated with risk for endometriosis, such as early age at menarche, ^(4-6) late menopause, frequent menstrual cycles ^(7,8) low parity,  ^{(6, 9,10)} use of oestrogen pills, ⁽¹¹⁾ oestrogen producing tumours,  obesity has also been  put forward. ^{(12, 13)} The cause of endometriosis is unclear, but several theories have been reported. One possible mechanism is retrograde menstruation. This retrograde flow, along with potential hematogenous or lymphatic circulation, may result in the seeding of endometrial tissue in ectopic sites. Another theory is direct implantation of endometrial tissue during surgical procedures like LSCS, Hysterectomy, Myomectomy, Episiotomy etc. Other factors, such as genetic, environmental, hormonal, inflammatory or immunological may also result implantation of endometrial tissues on ectopic sites.  ^(14-17)

          Clinical presentation of endometriosis varies in women. Patients often present with symptoms such as inter menstrual bleeding, dysmenorrhoea, dyspareunia, dyschezia and dysuria^{. (18)} Pelvic pain may present before onset of menstruation. Often, endometriosis can be asymptomatic, only diagnosed during evaluation for infertility. The lesions can be peritoneal lesions, superficial implants or cysts on the ovary, or deep infiltrating disease. ⁽¹⁹⁾ Classification of endometriosis associated symptoms have been established by the American Society for Reproductive Medicine (ASRM) based on the morphology of peritoneal and pelvic implants such as red or pink, white and black lesions, percentage of involvement of organ. Endometriosis in bowel, urinary tract, fallopian tube, vagina, cervix, skin or other locations are identified as per ASRM guidelines. Stages of endometriosis according to ASRM guidelines are stage I, II, III, and IV. These are based on the point scores and correspond to minimal, mild, moderate and severe endometriosis. Early diagnosis and intervention could ultimately improve the quality of life and preserve fertility. ⁽²⁰⁾

Objective: The goal of this paper is to highlight an atypical case of scar endometriosis.

Case report:                                                                    

            A 39 years old female patient came to Gynaec OPD of NIUM Hospital on 6^th May 2019 with the complaint of supra pubic swelling which was gradually increasing in size since last 6 months. She also complained that the pain in lump is worse during menstruation. Her age of menarche was 15 years. She is having regular menstruation with normal flow, but history of dysmenorrhoea is present. She had no history of other systemic illness. Her married life was 18 years. She had two children both were delivered by LSCS and history of one spontaneous abortion was also present. The patient was tubectomized after caesarean section. Her last child birth was 10 years back. According to her history before surgery she was fit and well with no documented history of endometriosis. Vitals were normal and her BMI was 26.2 Kg/m2.

            On examination a supra pubic swelling size approximately 8X5 cm was found at the site of lower part of caesarean scar. On palpation local temperature was raised, mass was irregular extending to pelvic region. (Figure.1) On vaginal examination uterus found anteverted, bulky, mobile and fornices free. On initial examination it was diagnosed as a lump. Consultant gynaecologist advised for USG and Cytology of lump. USG was done on 14/5/2019 findings suggested that large well defined hypoechohic solid lesion approximately 8.6X6.5X7.1cms noted in subcuteneous plane in mid line of lower anterior abdominal wall and supra pubic region suggestive of endometriosis.  For confirmation FNAC was done on the same day i.e. 14/5/2019 which reported benign cellular stromal fragments of endometrium with occasional benign glands. No granuloma or malignancy was found. These findings suggested endometriosis. Extra abdominal endometriosis occurs at the time of surgical procedures like myomectomy, hysterectomy or LSCS etc. Here in this case previous history of two LSCS was present, which suggested the swelling may be due to direct implantation of endometrial tissue during caesarean section. This endometrial tissue grows every month in response to hormones especially oestrogen.  Oestrogen helps in proliferation of endometrial tissue every     month, hence the supra pubic swelling was increasing slowly.

Discussion:

             Scar endometriosis is rare entity usually follows previous abdominal surgery, especially early hysterectomy and caesarean section. There are numerous sites where extra pelvic endometriosis has been reported. These include lungs, pleura, bladder, kidney, bowel, omentum, umbilicus and abdominal wall. ⁽²¹⁾Endometriosis involving the abdominal wall is a rare occurrence, however, it should be considered in the differential diagnosis of abdominal wall masses in females. The typical clinical scenario involves a parous female with a history of gynaecological or obstetrician surgery presenting with a painful nodule or lump. The severity of pain and size of the lump may vary with menstrual cycle. In this case the patients remained without a diagnosis for 10 years. Gynaecological history and physical examination is important in finalizing the diagnosis. The history revealed that the pain coincide with her menstrual cycle. The clinical examination revealed a soft, non reducible swelling located in pubic region. It was tender on palpation. On initial examination it was diagnosed as a lump. Based on the gynaecological history of a cyclical increase in the size and severity of pain an endometrioma was also included in the differential diagnosis. ⁽²²⁾

           Surgical scar endometriosis is believed to result from deposits of endometrial cells during surgical intervention. These cells are then stimulated by oestrogen to produce endometriomas. Although relatively uncommon, it was well documented in clinical practice that scar endometriosis occur with different types of incisions where contact has possibly occurred with endometrial tissue.⁽²³⁾ The endometriomas may develop 1-20 years post operatively, example include caesarean section, laparoscopy, tubal ligation and hysterectomy. Of these caesarean section and hysterectomy are the most common. ⁽²⁴⁾ The incident after caesarean section is difficult to determine, but estimates range from 0.03% to 0.47%.  ⁽²⁵⁾ Minaghlia et al analyzed 30 years of incisional endometriosis after caesarean section reported the incidence of scar endometriosis to be 0.08%. ⁽²⁶⁾ Frequency of scar endometriosis increase by number of caesarean section and laparoscopy performed in recent years. ⁽²⁷⁾ Other authors have reported an incidence of 0.2% in all caesarean sections performed. ⁽²⁸⁾ To make a definitive preoperative diagnosis of endometriosis is difficult. ⁽²⁸⁾

Positive histology confirms the diagnosis of endometriosis; negative histology does not exclude it, whether histology should be obtained if peritoneal disease alone is controversial. Visual inspection is usually adequate but histological confirmation of at least one lesion is ideal.  Compared to laparoscopy, transvaginal ultrasound has no value in diagnosing peritoneal endometriosis, but it is a useful tool both to make and to exclude the diagnosis of an ovarian endometrioma. TVS may have a role in the diagnosis of disease involving the bladder or rectum. Medical imaging plays a role in locating the mass and ruling out hernia and other conditions, for example lipoma, abscess and suture granuloma. MRI remains the most useful imaging modality to exclude other pathology. ⁽²⁸⁾ In this case the scar endometriosis was diagnosed by USG and was confirmed by FNAC of the lump.

Conclusion:

            Endometriosis is a debilitating disease that impacts the quality of life of adolescent and adult patients. Delayed diagnosis is common and may lead to a decline in reproductive potential and fertility. A semi or non-invasive diagnostic biomarker would be a useful tool to identify patients early in the disease process and thus improving outcomes, including less pain and better fertility. The occurrence of abdominal wall scar endometriosis after caesarean section has been a definite entity; steps to prevent this complication have not been explained. Literature recommends that through cleaning, irrigation with saline and closure of abdominal wound will prevent scar endometriosis.

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