Endometriosis arising in a cesarean section scar: A case report

A 38-year-old woman who presented with a markedly tender ulcerated mass (4 cm in widest dimension) in the upper 1/3 of a sub-umbilical midline cesarean section scar [ Fig. 1 ]. On examination the patient was in pain and unable to stand upright. An abdominal ultrasound scan showed normal intra-abdominal findings. Fig. 1 Photography of the cesarian section scar showing a bourgeonanting mass. Fig. 1 Photography of the cesarian section scar showing a bourgeonanting mass. The swelling was first noticed by the patient 9 months ago and had become progressively larger and more painful. Four months after it first appeared the patient noticed that the swelling would ulcerate, bleed and become painful for three days or so every month during her menstrual period. The patient had delivered three children between 11 and 16 years prior to presentation, the first was delivered by cesarean section, and two subsequent children were by normal vaginal delivery. For 7 years prior to presentation the patient was on three monthly injections of Depo-Provera for contraception. The history and examination made endometriosis of the cesarean section scar a likely diagnosis, which was confirmed by histology after full thickness wide excision of the mass [ Fig. 2 , Fig. 3 ]. The patient was discharged uneventfully from the hospital on the 2nd postoperative day. On follow-up, 3 months later, she had no complaints and was fully recovered [ Fig. 4 ]. Fig. 2 Photography of intra-operative findings showing the cesarian section scar's mass after full resection. Fig. 2 Fig. 3 Histology pictures showing benign skin with underlying stroma being infiltrated by island composed of benign endometrial glands and stroma associated with extracellular hemorrhage and chronic inflammation suggestive of endometriosis. Fig. 3 Fig. 4 Photography of the scar 3 months post-surgery. Fig. 4 Photography of intra-operative findings showing the cesarian section scar's mass after full resection. Histology pictures showing benign skin with underlying stroma being infiltrated by island composed of benign endometrial glands and stroma associated with extracellular hemorrhage and chronic inflammation suggestive of endometriosis. Photography of the scar 3 months post-surgery.

MR managed the patient and SMK and FKS wrote the first draft. All authors read and approved the final manuscript.

Not applicable.

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

The author FKS was supported by Safe Surgery DRC (SS-DRC). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Not applicable.

Franck Katembo Sikakulya

Endometriosis arising in a cesarean section scar is an uncommon form of extra pelvic endometriosis. Although there is a wide differential diagnosis for swellings of the abdominal wall, it should be suspected in any female patient with a lesion in surgical scar, which becomes more painful and swollen during her menstrual period. Unfortunately, not all patients have this presentation. There is not much to do in preventing occurrence of this condition in those that are predisposed however the role of the surgeon is a high index of suspicion, early diagnosis and surgical intervention to limit the morbidity and/or prevention of malignant transformation.

Although endometriosis development in surgical scars is most often seen after cesarean section [7] , it can develop after a variety of other procedures, such as hysterectomies, cystectomies, tubal ligations, amniocentesis [8] , episiotomy [9] , appendectomies, umbilical hernioplasty, and laparoscopic trocar tracts [10] , [11] . Implantation of endometrial tissue into a surgical incision has been proposed as an explanation of the condition's pathophysiology [12] . It is thought that during a cesarean delivery endometrial tissue is inoculated into the incision. With an appropriate supply of nutrients and hormonal stimuli, these endometrial cells survive and proliferate if there are sufficient nutrients and the appropriate hormonal environment [7] . The differential diagnosis of abdominal wall endometriosis includes abscess, lipoma, hematoma, granuloma, neuroma, sebaceous cyst, incisional hernia, lymphoma, sarcoma, etc. [13] . The clinical presentation may be variable and, as in our patient, may not occur until years after surgery. If present, an important clinical clue is a slowly growing painful palpable mass in the area of an old scar, which increases in size and becomes more painful during menstruation. Although pain is the predominant symptom and occurs in almost all cases, unfortunately almost half of patients do not exhibit the condition's characteristic periodicity in pain [14] . Histology examination remains the diagnostic test of choice [15] . Administration of hormonal preparations offer only temporary relief of symptoms [16] . Wide surgical resection of ectopic endometriosis is the treatment of choice, even for repeated recurrent lesions. It is usually curative and ensures the confirmation of diagnosis. The prognosis of ectopic endometriosis is good with an immediate relief of the symptoms after surgery. Unfortunately, scar associated endometriosis can undergo malignant transformation [5] . Although CT scan and MRI are better able to determine the extent of infiltration of adjacent tissues by ectopic endometriosis [17] , ultrasound scan was the only investigation available to this patient. Our patient's ultrasound examination was normal, and ultrasound is a practical and affordable method of patient follow-up in a low resource setting [18] . In addition to early detection, serological markers can be used for postoperative monitoring to detect both recurrence and malignant transformation. Although cancer antigen 125 ( Ca125 ) over 1000 UI/ ml has a specificity of 83–93% for invasive disease [14] , its sensitivity has been reported to range from 24 to 94% [19] . Therefore, this test may not be a reliable screening test.

Not commissioned, externally peer-reviewed.

Endometriosis was first described by Karl Von Rokitansky in 1860, who defined it as the presence and development of functional endometrial tissue in locations other than the uterine lining [1] . Major sites for extra-pelvic endometriosis include the lungs, pleura, kidneys, bladder, omentum, bowel, lymph nodes, and abdominal wall [2] . The incidence of endometriosis developing in a surgical scar after cesarean section is reported to be 0.03–0.45%, and it may cause long-term discomfort and cyclic lower abdominal pain [3] , [4] . Variability in clinical presentation and lack of knowledge about the disease may lead to misdiagnosis and delay in management, which have negative and possibly life-threatening consequences for the patient's wellbeing and quality of life with a risk of malignancy transformation [5] . This case report has been reported in line with the SCARE 2020 criteria [6] .

cesarean section cancer antigen 125 cesarean section Endometriosis computed tomography scan magnetic resonance imaging sub-umbilical midline scar spontaneous vaginal delivery

The authors declare no conflicts of interest.

All data generated or analyzed during this study are included in this published article.