Ruptured Ovarian Mature Teratoma in a Pregnant Woman with Severe Chemical Peritonitis: A Case Report

Introduction

Mature cystic teratomas (MCTs), also known as benign cystic teratomas or dermoid cysts, are the most common germ cell tumors, accounting for about 25% of all ovarian neoplasms [1]. While these tumors can occur in children and postmenopausal women, they are most common during the reproductive years. MCTs are frequently identified in the second trimester and affect about 0.3% of pregnancies [2]. During pregnancy, complications associated with MCTs include torsion, rupture, and obstruction during labor [3]. Rupture of a MCT during pregnancy has been shown to mimic ovarian malignancy, cause acute peritonitis and infection, and lead to preterm delivery [3–5]. This report describes a ruptured MCT leading to chemical peritonitis in the second trimester of pregnancy, ultimately leading to an uncomplicated, full-term delivery.

Case Report

A 31-year-old woman who was gravida 4, para 1, aborta 1 presented to our Labor and Delivery Department at 26 weeks 0 days gestation with intermittent cramping and suprapubic pain for 24 h associated with urinary frequency, urgency, and flank pain. She denied dysuria or gastrointestinal symptoms. Her gynecological history was significant for a 7-cm dermoid cyst noted on ultrasound 5 years prior; however, her anatomy ultrasound during this pregnancy only identified a 2-cm simple cyst. Her medical history was only significant for normocytic anemia. On physical exam, she had notable tachycardia and diffuse abdominal tenderness without guarding or rebound. Her pelvic exam showed tenderness of the posterior fornix with no cervical motion tenderness. Leukocytosis with a left shift was identified. Electrolytes, amylase, lipase, and liver function test results were normal. Since the patient was not being worked up for sepsis, CRP and procalcitonin were not collected. Tumor markers were also not collected, as no tumor was initially identified on ultrasound. An incidental finding of bacterial vaginosis was noted on vaginal culture collected on admission and was treated with metronidazole. An abdominal ultrasound and all other initial labs (sexually transmitted infection panel, pancreatic enzymes, and electrolytes) were unremarkable. Fetal tachycardia was identified during fetal monitoring; this improved after intravenous hydration and acetaminophen administration. The patient was noted to have 2 contractions in 10 min and pre-term labor was ruled out. Tocolysis was not indicated, as the patient was not in labor and the contractions were non-painful. Additionally, given the leukocytosis on presentation with concern for an infection of unknown origin, tocolysis was held pending a full evaluation. Contraction strength was unable to be calculated, as the patient was being monitored with external monitoring.

Despite pain medication and intravenous hydration, the patient continued to have persistent, cyclical pain with contractions. Due to concern for acute appendicitis, an MRI of the abdomen was performed and showed a heterogeneous collection of fluid in the pelvic cul-de-sac, with a normal-appearing appendix (Figures 1, 2). With a new working diagnosis of a ruptured hemorrhagic cyst, the goal was pain management, which was achieved with intravenous opioid and acetaminophen administration. However, on hospital day 3, her pain acutely worsened, and she now had nausea and vomiting; an abdominal exam showed significant tenderness and guarding. Due to her worsening condition, a diagnostic laparoscopy was offered. The working differential diagnosis included ovarian torsion, as well as non-gynecological causes.

The patient was taken for a diagnostic laparoscopy by the obstetrical team. Entry into the abdominal cavity was achieved using Veress entry at Palmer’s point due to the patient’s pregnant uterus. During laparoscopy, copious yellow-green purulent fluid was identified in the abdomen covering the visceral contents. The right fallopian tube was identified and appeared normal. There was poor visualization of the left fallopian tube, bilateral ovaries, and posterior cul-de-sac due to the gravid uterus. An evaluation of the entire abdominal cavity showed Fitz-Hugh-Curtis adhesions near the liver and dilated loops of bowel. The pelvis was profusely irrigated and the peritoneal fluid was sent for pathological evaluation. An intraoperative general surgery consultation was not obtained due to surgeon preference. The fetal heart rate was confirmed twice, after the induction of anesthesia and at the end of the case.

After the procedure, the differential diagnosis was amended to include a ruptured tubo-ovarian abscess (TOA), given the purulent peritoneal fluid and the Fitz-Hugh-Curtis adhesions identified. The patient had significant improvement in pain after the procedure. She was started on piperacillin-tazobactam due to suspicion for a TOA. To prevent preterm labor, prophylactic indomethacin was started for tocolysis, given the patient’s gestational age and recommendations from the American College of Obstetricians and Gynecologists. Nifedipine is generally used for tocolysis after 32 weeks of gestation and therefore was not considered. An alternative agent, Atosiban, is not approved for use in the United States. After a discussion with the in-house perinatologists, the decision was made to forgo antenatal corticosteroids due to the low risk of delivery within the next week. This was done after a discussion of the risks and benefits with the patient.

The patient’s pain continued to improve, but on postoperative day 1, a marked decrease in hemoglobin was identified and the patient was transfused 2 units of packed red blood cells to correct her severe anemia. Given the significant drop in hemoglobin, a differential diagnosis of intra-abdominal bleeding, occult placental abruption, or microangiopathic hemolytic anemia (MAHA) was considered. To rule out internal bleeding, a CT scan of her abdomen and pelvis was performed, with the maternal risk of bleeding greater than the fetal risk of irradiation. The CT scan showed a 5.7×9.8×6.6 cm mass in the cul-de-sac, with cystic, fat, and calcified components, along with intralesional areas of hemorrhage (Figures 3, 4). Her hemoglobin was trended after the blood transfusion over 3 days and found to be stable, eliminating the concern of continued intra-abdominal bleeding.

A ruptured teratoma was determined to be the likely source of the pain, which was continuing to improve postoperatively. Piperacillin-tazobactam was discontinued on postoperative day 2. The patient had an uncomplicated postoperative course, other than constipation, and was discharged on hospital day 8. The surgical cytology review was negative for malignant cells and notable for reactive mesothelial cells, macrophages, lymphocytes, and neutrophils. The remainder of the patient’s pregnancy progressed normally, with the patient following up at regularly scheduled intervals for routine prenatal care. The patient went into natural labor and delivered via a spontaneous vaginal delivery at 39w1d. Postpartum, she developed preeclampsia without severe features, which was followed up outpatient with regular blood pressure monitoring. After discharge, the patient was seen in the clinic and a bedside ultrasound confirmed a 14×9 cm mass posterior to the uterus. Given the size of the lesion, she was not counseled on ovarian torsion, but surgical planning included counseling on an open procedure. On postpartum week 9, the patient returned for a scheduled laparoscopic ovarian cystectomy. An 8-cm left teratoma with 7 loculations was identified and noted to be adherent to the pelvis bilaterally (Figures 5, 6). The entire cyst was resected and the procedure was uncomplicated.

Discussion

Mature cystic teratomas (MCT) are benign tumors composed of 1 or more of the 3 germ cell layers of the developing embryo – the ectoderm, mesoderm, and endoderm. Accounting for about 25% of all ovarian neoplasms, these benign lesions are typically unilateral, but are bilateral in about 10–15% of cases [1]. Usually asymptomatic, these tumors can cause severe pain if they lead to ovarian torsion or, in case of cyst rupture, reactive peritonitis. During pregnancy, triage of pelvic pain includes creating a differential diagnosis of both obstetric and gynecological etiologies, as well as other etiologies that may necessitate surgical intervention. As in this case, acute appendicitis was on the differential diagnosis given the acute onset of pain. Another less likely diagnosis is Meckel’s diverticulum; however, this was not considered given the patient’s age.

When a patient with a known prior ovarian cyst presents with abdominal pain, evaluation of cyst rupture or ovarian torsion using imaging is a reasonable part of the workup. The literature shows it is reasonable to expectantly manage asymptomatic MCTs identified during the second trimester of pregnancy [3]. Surgical management is another option. In a 1996 study by Parker et al, 12 women with MCTs were laparoscopically managed during pregnancy, with 93% of cases leading to intraoperative cyst rupture, and none of these women had a chemical peritonitis [6]. Another study, with non-pregnant patients, by Kocak et al in 2004 found comparable results, with 42.5% of cases leading to spillage, none of whom developed a chemical peritonitis [7]. In both these studies, the spillage was iatrogenic at the time of cystectomy. In our patient’s case, the gradual onset of chemical peritonitis was due to spontaneous rupture of a preexisting MCT. Intraoperatively, the identification of the chemical peritonitis was found to be the likely source of the pain. The patient’s gravid uterus did not allow for visualization of the cyst intraoperatively, leading to the false conclusion that there was a ruptured tubo-ovarian abscess.

Iatrogenic spillage during a cystectomy during pregnancy can be corrected with copious irrigation of the pelvis to minimize the risk of chemical peritonitis [6], which suggests that a reasonable treatment for a spontaneously ruptured MCT in pregnancy is peritoneal washout during a diagnostic laparoscopy. Our patient’s pain significantly improved postoperatively after undergoing a pelvic washout during laparoscopy. Treatment of a ruptured MCT can also include the initiation of antibiotics postoperatively, which we chose to implement in our patient [4].

Identification of the cyst preoperatively would have been ideal, but transabdominal ultrasound and MRI failed to identify the lesion. A complex ovarian mass was on the differential diagnosis; however, the radiologist’s primary reading of the MRI images suggested a ruptured hemorrhagic cyst was more likely. On independent evaluation of the images, they were noted to be unclear and obscured by the location of the fetus in relation to the cyst. A pelvic ultrasound was limited due to the patient’s pain, leading to poor image quality. The diagnosis of a ruptured teratoma is difficult using only ultrasonography. A CT scan is about 93–98% sensitive for the identification of intraperitoneal fatty implants [4]. Based on ACOG recommendations, fetal risks of growth restriction, spontaneous abortion, or malformations have not been reported with radiation exposure less than 50 mGy [8]. A CT of the abdomen and pelvis generally has doses equal to or less than 50 mGy, thus serving as a safe and effective imaging modality for identification of a ruptured teratoma [8], especially in the third trimester. Ensuring the safety of the fetus was also a component of management. Per ACOG recommendations for performing a non-obstetrical surgery after viability, the fetal heart rate was monitored prior to and after surgery, and the patient provided consent for an emergency cesarean delivery [9].

Conclusions

As described in this case, a ruptured MCT is a reasonable addition to the differential diagnosis for acute-onset pelvic pain in pregnancy. There is no standard management of these cases; however, imaging and diagnostic laparoscopy can be used to manage an MCT. While ultrasound is the imaging modality of choice, it may be insufficient in the setting of a ruptured lesion or if the patient is experiencing severe pain and is unable to tolerate the exam. Despite the risk of radiation to the fetus, a CT scan may be the ideal modality in pregnancy in this setting. Followed by identification of the ruptured lesion, the management of the subsequent chemical peritonitis with a pelvic washout during laparoscopy can remove the inflammatory contents from the abdominal cavity and provide symptomatic relief.