Roughly 1%-2% of pregnancies are complicated by an adnexal mass, and prenatal ultrasound for fetal evaluation has detected more asymptomatic ovarian masses as a result.
The differential diagnosis for adnexal mass is broad and includes follicular or corpus luteum cysts, mature teratoma, theca lutein cyst, hydrosalpinx, endometrioma, cystadenoma, pedunculated leiomyoma, luteoma, as well as malignant neoplasms of epithelial, germ cell, and sex cord–stromal origin (J Ultrasound Med. 2004 Jun;23[6]:805-19). Most masses will be benign neoplasms, with a fraction identified as malignancies.
Dr. Allison Staley
In 2013, Baser et al. performed a retrospective study of 151 women who underwent surgery of an adnexal mass at time of cesarean delivery. Of the 151 cases reviewed, 148 (98%) of the masses were benign (Int J Gynaecol Obstet. 2013 Nov;123[2]:124-6). Additionally, if the patient presents with pain, diagnoses such as ectopic pregnancy, heterotopic pregnancy, degenerating fibroid, and torsion should also be considered.
Diagnostic evaluation and management
The majority of adnexal masses identified in pregnancy are benign simple cysts measuring less than 5 cm in diameter. Approximately 70% of cystic masses detected in the first trimester will spontaneously resolve by the second trimester (Clin Obstet Gynecol. 2006 Sep;49[3]:492-505). However, for some masses, surgical resection is warranted.
Masses present after the first trimester and that are (1) greater than 10cm in diameter or (2) are solid or contain solid and cystic areas or have septated or papillary areas, are generally managed surgically as these features increase the risk of malignancy or complications such as adnexal torsion, rupture, or labor dystocia (Gynecol Oncol. 2006 May;101(2):315-21).
Dr. Paola A. Gehrig
Adnexal masses without these features often resolve during pregnancy and can be expectantly managed (Obstet Gynecol. 2005 May;105[5 Pt 1]:1098-103). The optimal time for surgical intervention is after the first trimester as organogenesis is largely complete, therefore minimizing the risk of drug-induced teratogenesis, and any necessary cystectomy or oophorectomy will not disrupt the required progesterone production of the corpus luteum as this has been replaced by the placenta.
Preoperative assessment
For most cases, imaging with ultrasound is adequate for preoperative evaluation; however, in some cases, further imaging is needed for appropriate characterization of the mass. In this situation, further imaging with MRI is preferred as this modality has good resolution for visualization of soft tissue pathology and does not expose the patient and fetus to ionizing radiation. Of note, Gadolinium-based contrast should be avoided as effects have not been well established in pregnancy (AJR Am J Roentgenol. 2008 Aug;191[2]:364-70).
If there is concern for malignancy during pregnancy, drawing serum tumor markers preoperatively is typically not suggested. Oncofetal antigens, including alpha fetoprotein (AFP), human chorionic gonadotropin (hCG), carcinoembryonic antigen (CEA), and cancer antigen 125 (CA-125), are elevated during gestation, making them poor markers for malignancy. If malignancy is ultimately diagnosed, then tumor markers can be obtained immediately postoperatively.
Surgical approach and prognosis
If there is low suspicion for malignancy, a laparoscopic approach is preferable and reasonable at all stages of pregnancy, although early second trimester is ideal. Entry at Palmer’s point in the left upper quadrant versus the umbilicus is preferable in order to minimize risk of uterine injury.
If malignancy is suspected, maximum exposure should be obtained with a midline vertical incision. Peritoneal washings should be obtained on immediate entry of the peritoneal cavity, and the contralateral ovary should also be adequately examined along with a general abdominopelvic survey. If the mass demonstrates concerning features, such as solid features or presence of ascites, then the specimen should be sent for intraoperative frozen pathology, and the pathologist should be made aware of the concurrent pregnancy. If malignancy is confirmed on frozen pathology, a full staging procedure should be performed and a gynecologic oncologist consulted.
Roughly three-quarters of invasive ovarian cancers diagnosed in pregnancy are early stage disease, and the 5-year survival of ovarian cancers associated with pregnancy is between 72% and 90% (Int J Gynecol Cancer. 2006 Jan-Feb;16[1]:8-15).
In a retrospective cohort study of 101 pregnant women, 31% of adnexal masses resected in pregnant women greater than 14 weeks gestation were teratomas. In total, 23% of masses were luteal cysts. Less commonly, patients were diagnosed with serous cystadenoma (14%), endometrioma (8%), mucinous cystadenoma (7%), benign cyst (6%), tumor of low malignant potential (5%), and paratubal cyst (3%).
In this study, approximately half of the women underwent minimally invasive surgery and half had surgery via laparotomy. There were more complications in the women undergoing laparotomy (ileus) and there were no differences between the groups with regards to pregnancy and neonatal outcomes (J Minim Invasive Gynecol. 2011 Nov-Dec;18[6]:720-5).