Unusual polypoid endometriosis with initial impression of abdominal ectopic pregnancy, discovered accidentally: case report and literature review

A 16-year-old nulliparous woman, married for 10 months, with no previous surgical history, was brought to a rural hospital with a history of vaginal bleeding for 15 days and pain in the left iliac fossa that recently got worse. She could not remember her last menstrual date and claimed she was almost three months pregnant. A primary diagnosis of a ruptured ectopic pregnancy was made and an exploratory laparotomy was decided. During the operation, severe adhesions were found, an enlarged left fallopian tube, and a mass posterior to the uterus. The mass was suspected to be products of conception, including a placenta, resulting from an abdominal ectopic pregnancy. Due to lack of surgical resources and experience at the rural hospital, the findings were left in situ, a drain was placed, and the patient was referred to our hospital, “Tawlied University Hospital,” for further management. Unfortunately, we were not provided with details from the rural hospital about the patient, and we had a lot of questions. We did not know whether the pregnancy was confirmed via serum bhcg measurement prior to the surgery or if an ultrasound was performed before the operation. As a developing country, we face many cases of misdiagnosis due to lack of surgical resources. However, upon arrival at our hospital, clinical examination showed hemodynamic instability (blood pressure of 100/60 mmHg and a pulse rate of 115 bpm, there was also weakness and pallor). Urgent abdominopelvic ultrasonography was performed, and it showed a left adnexal mass and severe free fluid in the abdominal cavity. The patient’s blood tests upon admission were as follows: white blood cells (19 000 10 9 /L), hematocrit 36.4%, hemoglobin 11.9 g/dL, and bhcg 183.2 mIU/mL. There was no time for further investigation, so to avoid her condition deteriorating to the verge of hypovolemic shock, we decided to perform an emergency exploratory laparotomy under general anesthesia. Skin sutures were removed, and the abdomen was reopened via a Pfannenstiel incision. After accessing the abdominal cavity, free hemorrhagic fluid was found, and the pouch of Douglas was filled with many blood clots. Approximately, 1000 mL of bloody fluid was evacuated from the peritoneal cavity by the suction. The uterus was tightly adhered to the sigmoid colon and rectum, as was the left fallopian tube, which was found to be hydrocsalpinx and also adhered to the left ovary and sigmoid colon. There was also a rupture in the round ligament of the uterus and bleeding in the uterine horn as a result of a previous dissection at the rural hospital. When examining the abdominal cavity, a solid cystic mass measuring 3 cm × 3 cm arising from the Douglas pouch was found (Fig. 1 ). It seemed to be distinct from the rectum, and no pedicle attached it to the uterus with an extremely high blood supply. Figure 1. Photograph of the resected mass from Douglas pouch, which was thought to be placenta and fetal tissues. Photograph of the resected mass from Douglas pouch, which was thought to be placenta and fetal tissues. Due to severe adhesions, we had to release the adhesions on the sigmoid colon and intestinal loop from the left adnexal mass, then we removed the left fallopian tube and the nodular lesion for pathological evaluation. Additionally, the appendix was found to be inflamed and removed. A drain was placed in the Douglas pouch, then the abdominal layers were closed. Intraoperatively, the patient received 1 unit of blood and 2 units of fresh plasma. Pathology results subsequently revealed chorionic villi in the fallopian tube, suggesting an ectopic pregnancy, and the appendix was acutely inflamed. The 3 cm × 3 cm solid cystic mass suggests benign PE with some cystic area (Fig. 2 ). Figure 2. Photomicrograph of the resected mass showing endometrial glands and stroma. Photomicrograph of the resected mass showing endometrial glands and stroma. At her 5-day follow-up appointment, her examination was within normal limits, and she was discharged and followed up at an outpatient clinic.

According to published studies, polypoid endometriosis (PE) is a rare form of endometriosis. It may produce masses mimicking neoplasms or cause diagnostic quandaries, particularly when the patient age, location, and/or epithelial appearance are atypical [ 1 ] . Many Cases are referred because of the suspicion of malignancy, largely because of the resemblance to a low-grade Mullerian neoplasm. PE is more common in pre- to postmenopausal women [ 2 ] and presents by pelvic mass, vaginal masses, and large bowel obstruction [ 2 ] . It has been associated with tamoxifen [ 3 ] , unopposed estrogen or combined estrogen-progestin therapy [ 4 ] , and pregnancy [ 5 ] . Interesting, none of these characteristics were present in our case, which indicates that the published studies that are limited to small case series and case reports are still insufficient. We present a rare case of PE in a 16-year-old nulliparous woman with no history of tamoxifen or combined estrogen-progestin therapy and no history of surgery who was accidentally diagnosed with PE during a surgical procedure for an ectopic pregnancy. The work has been reported in line with the SCARE criteria [ 6 ] .

PE is a distinct mass-like variant of endometriosis with histological features similar to those of endometrial polyp [ 7 ] . The term was first introduced by Motorized and Scully in 1980 [ 7 ] . The literature on PE is limited to small case series and case reports; the largest case series was published by Parker et al [ 4 ] and only included 24 cases, so this entity is not well known. Because PE forms masses, it is misdiagnosis, as it usually mimics tumors and is mistaken for neoplasm on clinical or intraoperative assessment [ 2 , 4 , 8 ] . Fortunately, in our case based on the clinical scenario (the patient’s young age, acute abdomen, and symptoms of ectopic pregnancy), an abdominal pregnancy was suspected instead of malignancy, which led to avoiding excessive surgical restriction in this patient, and thus preserving her fertility. According to previous studies, PE mainly affects older women (typically pre- or postmenopausal in age) compared with patients with classic endometriosis, which usually presents before menopause. [ 2 , 4 ] It is associated with exposure to Tamoxifen and hormonal replacement therapy, where nearly 50% of patients with PE were on hormonal treatment (either unopposed estrogen or mixed estrogen/progestin therapy) at the time of diagnosis. [ 9 , 10 ] But contrary to the literature, this is the first reported case of a woman who was only 16 years old, and this is the youngest age at which this condition is diagnosed according to the literature. Furthermore, she has no history of medication, including hormonal therapy which suggests that the specific mechanism still needs further study and exploration. The most common clinical presentations were pelvic masses, vaginal polypoid masses, and large obstructions [ 3 ] . Our patient did not have any of these symptoms, but only suffered from untreated profound dyspareunia. Neglecting this complaint led to discovering the disease incidentally during laparotomy for another reason. However, discovering the disease led to avoiding the consequences of diagnostic errors that might occur later if it had not been discovered and remained silent, such as confusion with malignancy and extensive surgery. The disease may involve various pelvic and peritoneal sites, and the rectosigmoid colon has been reported to be the most frequent site of involvement, followed by the ovary. [ 11 ] The definitive diagnosis of PE still requires histopathology. According to the literature, a prior diagnosis was only made before histological examination in two cases diagnosed preoperative based on MRI imaging findings as PE [ 12 ] .

PE has a clinical presentation different from non-PE. It may be seen at young ages, not just pre- or post-menopause, and it is not always related to hormonal therapy. PE should be part of the differential diagnosis of young women presenting with pelvic mass, regardless of the medication history of the patient. Tumors are not the only differential diagnosis but may cause other diagnostic problems depending on the clinical context, and we believe that our report will broaden the diagnostic thinking for similar cases.