Presence of ectopic endometrial tissue outside the uterine cavity is defined as an ‘endometriosis’. Pelvic endometriosis is more common than extra-pelvic one, while extra peritoneal variety is least common. Endometriosis along the incision may be on abdominal wall or at vulvo-vaginal region.1 Wepsi1 suggested that the frequency of scar endometriosis might approach 5% among patients having caesarean section or hysterotomy.Violation of endometrial cavity has been reported to greatly facilitate the transportation of ectopic endometrium. In vulvo-perineal region, scar of colpo-perineorrhaphy, episiotomy and bartholin cyst excision can be a site of endometrial implantation. Also, endometriosis has been reported along the needle tract after amniocentesis or intra-amniotic saline instillation for second trimester abortions.

Material and Methods

This data is of six cases of scar endometriosis from single working unit of department of obstetrics and gynaecology of L.T.M.G. Hospital, Sion over a period of four years.

History regarding basic data, preceding operation, time interval and symptomatology was taken. Classical symptom of cyclical swelling and tenderness over nodule along the scar was asked. Apart from examination of lesion over the scar, pelvic examination was done to detect any induration, shotty feel and fixity of uterus with mass in the fornix and thus to detect or exclude presence of pelvic endometriosis. All patients were called during menses for confirmation i.e. looking for increase in size of the nodule and induration etc.

In patients requiring surgical removal, tissue was sent for histo-pathological examination. The site and extent of lesion was confirmed during surgical removal.

Results

Majority of the patients were between 20-30 years of age, one of them being nulliparous infertile patient. Caesarean section and hysterotomy were preceding operations in two patients each, while one patient had undergone myomectomy with chocolate cyst removal in past. One patient with vulvo-vaginal endometriosis had history of normal delivery six months back. The discharge paper of this patient revealed that she had undergone curettage after delivery for post-partum haemorrhage.

The interval between preceding operation and appearance of symptoms is shown in Table 1. All patients complained of pain and swelling along the scar with cyclical increase during menses. One patient had ulcerative superficial lesion on the perineum. Associated symptoms like pain in abdomen and menorrhagia was seen in two patients, while one patient complain of dyspareunia.

Three patients had vertical scar while two had pfannenstein one.On examination, single big tender nodule beneath or on side of scar was detected in four cases, while one case had three small nodules seen along the vertical scar. One patient had small superficial nodule, bleeding intermittently, at vulvo-vaginal junction at episiotomy scar. All patients were examined during menses to note increase in symptoms and signs.

Two patients were started on progesterone therapy. One of them responded well in first three months, later on did not follow up. The other one did not respond to this treatment at all and required surgical excision.

Thus four patients with abdominal wall lesions required surgical treatment. In two women, only skin and subcutaneous tissue was involved , while in other two cases, even muscle and sheath was involved. In these two cases, peritoneum was opened to find or rule out present pelvic involvement. In one patient, we did find a band with endometriotic nodules running from incision to anterior part of uterus with few pelvic lesions. Excision of scar with band along with coagulation of pelvic endometriotic spots was carried out. Post- operatively, patient was started on danozol therapy and responded well. In patient with vulval endometriosis, excision of lesion was done.

Histo-pathological examination confirmed the diagnosis of endometriosis.

Observations and analysis
Discussion Endometriosis of scar tissue is a known entity following operations violating uterine cavity allowing lining of endometrium to get implanted elsewhere. Hysterotomy and caesarean section are the most common operations associated with scar endometriosis2, but it is also seen, rarely, following myomectomy, tubal ligation and even hysterectomy. Dutta3 and Pal4 have published large series of scar endometriosis and reported hysterotomy as the most common operation leading to this condition. It is likely that during hysterotomy or caesarean section, decidual cells spill and implant on the abdominal wound. After being transported to the susceptible wound with high degree of pluropotentiality, decidual cells do not proliferate themselves but stimulate metaplasia in the lodging tissue that form the endometriosis.5 It undergoes changes with ovulatory cycles and bleeds in the tissue at the time of menstruation. Thus it is important to do careful flushing and irrigation of the abdomen and incision during closure to avoid possible contamination. Perineal implantation of ectopic endometrium along the episiotomy scar is uncommon. We came across one such case, where there was a history of curettage to remove retained bits of placenta. Considering the magnitude of scope of such implantation during vaginal delivery, it is possible that hormonal effects of puerperium on endometrium provide adverse conditions for implantation and growth. The aetiology of endometriosis is an enigma. It is not known why it takes few months to years after operation to develop clinically significant endometriosis in the scar. With better understanding of aetio-pathogenesis of endometriosis, we may be able to get more satisfactory answers. Though scar endometriosis is less responsive to hormonal treatment, it can be tried in cases with small nodule or prior and after the surgical excision. Surgical excision is the best option, both diagnostic and curative. It also helps to exclude malignancy in the ectopic endometrium, which is a rare possibility. References

1. Wepsi HJ, Kletzhandler M. Uber Narbenendometriosen. Mschr Geburtsh Gynakol 1940; 111 : 169-75. 2. William TJ. Endometriosis, Te Lindes operative Gynaecology 6th Edition, 1985, Harper and Row Publishers , Asa P- 267. 3. Dutta DK, Dutta B, Scar endometriosis- a clinico pathological study. J Obst Gyn India 1992; 42 : 831-4. 4. Pal A, Sarkar P, DuttaGupta H. Scar endometriosis. J Obstet Gynecol India 1991; 41 : 537-40. 5. Ridley JH. The histogenesis of endometriosis: A review of facts and fancies. Obstet Gyn Surv 1968; 23 : 1-14.