Uterocutaneous fistula associated with scar endometriosis following cesarean section: A rare case report

Scar endometriosis is a rare extrapelvic manifestation of endometriosis that most commonly occurs following cesarean section due to iatrogenic implantation of endometrial tissue. Uterocutaneous fistula, an abnormal communication between the uterus and the s kin, is an exceptionally uncommon condition and its coexistence with scar endometriosis presents significant diagnostic and surgical challenges. We report a case of a 35 -year-old woman, P1L1, with a history of lower segment cesarean section 12 years ago, presented with dysmenorrhea, heavy menstrual bleeding, and cyclical bleeding from a sinus located 3 cm below the umbilicus since past 3 -4 months. Clinical examination revealed a nodular infraumbilical mass with a sinus tract of approximately 2x2 cm. Ultraso nography suggested scar endometriosis, while magnetic resonance imaging demonstrated a well -defined enhancing lesion with a communicating tract to the anterior uterine wall of approximately 1.5 cm in length and 5.7 mm width, associated adhesions, and right haematosalpinx. A provisional diagnosis of scar endometriosis with uterocutaneous fistula was made. The patient underwent wide excision of the lesion with fistula tract ablation, right salpingectomy, left ovarian cystectomy, and abdominal wall reconstruct ion with mesh reinforcement. Postoperative recovery was uneventful. This case highlights the importance of clinical suspicion, advanced imaging for preoperative planning, and complete surgical excision for successful management.

Scar endometriosis, uterocutaneous fistula, cesarean section, haematosalpinx, abdominal wall reconstruction

Endometriosis is defined as the presence of functional endometrial glands and stroma outside the uterine cavity [1]. It commonly affects pelvic struc tures such as ovaries, uterosacral ligaments, and pouch of Douglas [1]. Extrapelvic endometriosis, though rare, can occur in surgical scars, particularly following obstetric and gynecological procedures [1]. Scar endometriosis most frequently follows cesar ean section, with reported incidence ranging from 0.03% to 1% [2]. The most accepted theory for its development is direct mechanical implantation of endometrial tissue during uterine incision and closure [3, 4] . Patients typically present with cyclical pai n and swelling at the scar site, often associated with menstrual irregularities [3]. Uterocutaneous fistula, defined as an abnormal tract between the uterus and skin, is an exceptionally rare entity [5]. It may result from postoperative complications, infection, trauma, or endometriosis. The coexistence of scar endometriosis with a uterocutaneous communicating fistula is extremely uncommon and presents diagnostic and therapeutic challenges [5, 6]. We present a rare case of scar endometriosis with a uterocut aneous communicating fistula occurring 12 years after cesarean section, successfully managed surgically. Case presentation A 35 year old woman, P1L1, with a history of lower segment cesarean section 12 years ago, presented with dysmenorrhea and heavy mens trual bleeding for three months. She described cramping lower abdominal pain beginning with menstruation and reducing by the second day of the cycle. She reported regular menstrual cycles every 28-30 days, lasting 6-7 days, with passage of clots and usage of 3-4 pads per day. International Journal of Clinical Obstetrics and Gynaecology https://www.gynaecologyjournal.com ~ 519 ~ Notably, she complained of cyclical bleeding through a sinus opening of approximately 1.5 cm in length located 3 cm below the umbilicus during menstruation for the past 3 -4 months. The discharge was minimal and did not completely soak the cloth used. There was no history of postcoital bleeding, dyspareunia, bowel or bladder disturbances, decreased appetite, or weight loss. She had no known history of diabetes mellitus, hypertension, tuberculosis, epilepsy, asthma, or cardiac disorders. There was no prior blood transfusion. Family history was non-contributory. She was not tubectomised and reported no known drug allergies. Clinical examination On examination, her general condition was fair. There was no pallor or pedal edema. Cardiovascu lar and respiratory system examinations were unremarkable. Abdominal examination revealed a soft, non-tender abdomen. Local examination revealed a sinus opening approximately 3 cm below the umbilicus, between the umbilicus and previous LSCS scar. A hard nodular swelling measuring approximately 6 × 5 cm was palpable beneath the sinus opening. Per speculum examination revealed a healthy vagina with foul - smelling greenish discharge and minimal bleeding. The cervix appeared normal. On per vaginal examination, t he uterus was bulky, fixed, and pulled upwards with bilateral fornices free but non-tender. Investigations Routine laboratory investigations revealed hemoglobin was 10.8 g/dL, total leukocyte count was 7560/mm³, platelet count was 3.34 lakh/mm³, and renal function tests were within normal limits. HIV, hepatitis B, and hepatitis C serology were non - reactive. Pap smear was Negative for Intraepithelial Lesion or Malignancy (NILM). Ultrasonography of the abdomen and pelvis revealed a fairly well-defined lobulated predominantly hypo echoic lesion in the infraumbilical region suggestive of scar endometriosis. The uterus and bilateral ovaries were reported as normal in size, and there was no free fluid in the pouch of Douglas. Magnetic Resonance Imaging (MRI) prov ided further delineation. The uterus was bulky and retroflexed. A well - defined enhancing lobulated lesion with irregular margins was noted in the infraumbilical region consistent with scar endometriosis. Adhesions were observed between the anterior uterine wall and abdominal wall lesion, with obliteration of fat planes. A right -sided haematosalpinx measuring 5 × 3 cm was identified. The right ovary was bulky and displaced anteriorly with altered architecture. These findings raised suspicion of an infiltrative process. Based on clinical and radiological findings, a provisional diagnosis of scar endometriosis with uterocutaneous fistula was made. Surgical management After informed written consent, the patient underwent scar endometriosis excision with fistula tract ablation, right salpingectomy, and left ovarian cystectomy under combined spinal and epidural anesthesia. An elliptical incision encompassing the sinus tract and previous LSCS scar was made. Intraoperatively, a mass measuring 12 × 7 cm was identifie d on the anterior abdominal wall, 3 cm below the umbilicus. A well -defined fistulous tract communicating from the anterior uterine wall to the scar endometriotic tissue was noted. The lesion was excised completely with adequate margins, and the fistula tract opening over the uterus was ablated using bipolar cautery. The uterus was normal in size but showed endometriotic spots over its surface, which were ablated. The right fallopian tube showed haematosalpinx measuring 5 × 3 cm near the pouch of Douglas, an d right salpingectomy was performed. The right ovary was normal in size but densely adherent to the ileocecal junction. The left ovary was bulky with cystic areas; accidental puncture led to drainage of clear fluid, and cyst wall excision was performed. Estimated blood loss was approximately 750 mL. One unit of Packed Red Blood Ce lls (PRBC) was transfused intraoperatively, and another unit was administered on postoperative day one. A significant rectus sheath defect measuring approximately 6 –8 cm was noted following excision. Primary closure was difficult; hence, flap release was performed, and closure was achieved using modified Smead -Jones technique with polypropylene sutures. Mesh reinforcement was performed. A Romovac drain was placed, and layered closure was completed. Postoperative course The patient remained hemodynamically stable postoperatively. Intravenous antibiotics (cefazolin and metronidazole) and supportive medications were administered. The urinary catheter was removed on postoperative day on e. The drain and sutures were removed on postoperative day eleven, with healthy wound healing. She was discharged with advice regarding wound care, protein - rich diet, adequate hydration, ambulation, and avoidance of heavy lifting. She was advised follow -up for histopathological evaluation and to report immediately in case of bleeding, abdominal pain, or urinary symptoms.

Scar endometriosis complicated by a uterocutaneous fistula most commonly follows cesarean section and may present years after the surgery; this delayed presentation and variable symptomatology (cyclical pain, swelling, and especially cyclical bleeding from a scar) are well described in case series and reports. Several case reports corroborate our observation of long latency and c yclical wound bleeding as a red flag for uterocutaneous communication [1, 3]. Imaging-guided preoperative mapping is repeatedly emphasized in the literature because it changes operative strategy: ultrasound often identifies hypoechoic scar lesions, but MR I more reliably delineates fistulous tracts, adhesions, and associated pelvic disease (haematosalpinx/ovarian involvement) and thus better informs wide excision and reconstruction plans, as highlighted in Etrusco et al . and other reports that used MRI to p lan definitive surgery [4]. Pathophysiologically cyclical bleeding within implanted endometrial tissue produces chronic inflammation, fibrosis and adhesion formation that can progress to tract formation and eventual uterocutaneous communication; this mecha nism is described across multiple clinical reports and reviews and was implicated in both Hasan et al . and Gupta P et al . [3, 5]. These works also stress that factors such as incomplete uterine closure, infection, or retained material may act as cofactors, explaining why some scar implants evolve into fistulae while others remain confined nodules Therapeutically, the consensus from case reports is that hormonal suppression can be temporizing but definitive cure requires complete surgical excision of the end ometriotic lesion International Journal of Clinical Obstetrics and Gynaecology https://www.gynaecologyjournal.com ~ 520 ~ with total resection/closure of the fistulous tract; several reports demonstrate good outcomes with fistulectomy ± uterine repair, and when extensive abdominal -wall defects result, reconstruction (flap or mesh) is sometimes necessary [5, 6]. Our operative approach and need for mesh reinforcement mirror these recommendations and the published outcomes.

Scar endometriosis complicated by a uterocutaneous communicating fistula is an exceptionally rare but significant delayed sequela of cesarean section that should be suspected in women presenting with cyclical bleeding or discharge from a previous abdominal scar. Early recognition requires a high index of clinical suspicion, and advanced imaging, particularly MRI plays a crucial rol e in delineating fistulous tracts and associated pelvic pathology. Definitive management depends on complete surgical excision of the endometriotic tissue with meticulous removal of the fistulous tract and appropriate abdominal wall reconstruction when req uired. Timely intervention not only prevents recurrence but also alleviates chronic morbidity and improves quality of life. Conflict of interest: None Funding: None Acknowledgment: None

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