Endometrioma decidualization in pregnancy: not just about papillations

Endometrioma decidualization in pregnancy: not just about papillations Linked article: There is a comment on this article by Moro et al. Click here to view the Correspondence. Abstract Linked article: There is a comment on this article by Moro et al. Click here to view the Correspondence. Decidualized endometriomas are usually described as unilocular-solid or multilocular-solid ovarian masses with ground-glass echogenicity containing rounded and vascularized papillations1, 2. Endometriomas undergoing decidualization may resemble malignant ovarian masses, in particular borderline ovarian tumors3. To the best of our knowledge, there are no reported cases in the literature of decidualized endometriomas presenting as completely solid ovarian masses on ultrasound. A 32-year-old nulliparous woman was referred to our Gynecological Ultrasound Clinic at 20 weeks' gestation. The patient had undergone excision of a left adnexal endometrioma 9 years previously. The patient self-reported recurrence of bilateral endometriomas with no supporting ultrasound images or medical reports. Transvaginal ultrasound showed a 6-cm solid mass in the left adnexa with no acoustic shadows, and intense vascularization was observed on power Doppler (Figure 1, Videoclip S1). No healthy ovarian tissue was seen. A 3-cm cyst with a typical sonographic appearance of endometrioma3 was seen in the right ovary. No free fluid or other suspected lesions were found in the pelvis or abdomen. Based on the patient's history, our primary suspicion was atypical presentation of a decidualized endometrioma. However, invasive histology (i.e. endometrioid/clear cell ovarian cancer or metastatic cancer) could not be excluded. Solid masses are associated with a significant risk of malignancy and therefore surgical management should be considered4. The patient received counseling to discuss that malignancy could not be ruled out and surgery was proposed, which the patient declined. To exclude suspicion of metastasis, pelvic mass biopsy was proposed as an alternative to surgery and the associated procedural risks were explained, including false negatives and spillage of the cyst contents that can alter the prognosis in the case of a primary malignant ovarian pathology5. After counseling, the patient agreed to undergo ultrasound-guided fine-needle biopsy. Histological analysis confirmed decidualized endometriotic tissue with no atypia. The literature highlights that transvaginal ultrasound demonstrates sensitivity and specificity comparable to that of magnetic resonance imaging (MRI) for the diagnosis of ovarian masses during pregnancy; therefore, MRI was not performed. Considering the biopsy results and patient preference, an ultrasound-based surveillance strategy was planned. The patient underwent two additional ultrasound evaluations at 25 and 30 weeks' gestation, which showed stable cyst dimensions and morphology. The rest of the pregnancy was uneventful and the patient delivered at term via spontaneous vaginal delivery. The patient was followed up at 1 month postpartum and ultrasound revealed two left adnexal unilocular ovarian cysts adjacent to each other with ground-glass echogenicity measuring 3 cm and 2 cm, respectively (Figure 2). A 2-cm unilocular ovarian cyst with ground-glass echogenicity was observed in the right adnexal region. The patient remained asymptomatic and continued conservative management. The postpartum ultrasound findings suggest that decidualization transformed the two endometriomas on the left side into a solid mass, which reverted to typical sonographic presentation after delivery. This case illustrates that decidualized endometriomas may present as vascularized solid masses and not only as cysts with rounded vascularized papillations. Further studies are needed to clarify the ultrasonographic features of decidualized endometriomas during pregnancy. DATA AVAILABILITY STATEMENT Data sharing is not applicable to this article as no new data were created or analyzed in this study.