Decidualized ovarian endometrioma mimicking malignancy in pregnancy: a case report and literature review

Abstract

Background Ovarian endometrioma is a common gynecologic disease among reproductive-aged women. Pregnancy-related hormonal status may lead to changes of decidualization, which may resemble ovarian malignancies in sonographic appearance. Here we present a case of decidualized ovarian endometrioma clinically mimicking malignant transformation. Case presentation A 37-year-old pregnant woman presented to our hospital at 25 + 5 weeks of gestation with a persistent left adnexal mass that was first detected on routine ultrasound in the first trimester. Transvaginal and transabdominal ultrasound showed a cystic mass of size 8.4 × 5.8 cm in the left ovary with abundant blood flow signals in the papillary medium echo of the capsule wall and inner wall, raising concern for malignant ovarian tumor. After a multidisciplinary discussion, the patient underwent laparoscopic left salpingo-oophorectomy. The results of the frozen section revealed decidualized endometrioma and the final histopathology confirmed endometrioma with extensive decidualization. The patient’s postoperative recovery was uneventful and she was discharged on the 4th postoperative day. Conclusions Decidualized ovarian endometrioma is rare. Sonography and magnetic resonance imaging are helpful for differential diagnosis. Conservative management of expectant management and serial monitoring should be adopted if decidualized endometriosis is suspected.

Prediction of the Risk of Malignancy of Adnexal Masses during Pregnancy Comparing Subjective Assessment and Non-Contrast MRI Score (NCMS) in Radiologists with Different Expertise

“…Our results highlighted that the diagnostic accuracy was affected by the fact that, in rare cases, there may be subtle differences between a benign and a malignant lesion, causing misinterpretations, thus leading to an increase in false negatives or false positives for both the expert and the non-expert radiologists. One example in our study population, also reported in the literature, was the correct interpretation of decidualised endometrioma [26][27][28][29][30][31][32]. During pregnancy, decidual endometrium changes are due to high levels of progesterone, so endometrioma can undergo decidualisation.…”

Manifestations of Ovarian Cancer in Relation to Other Pelvic Diseases by MRI

“…During pregnancy, the ectopic endometrium is characterized by increasing glandular epithelial secretion, stromal vascularity, and oedema due to increased progesterone levels, a change defined as decidualization [ 108 ]. At imaging, decidualized endometrioma often appears as a cystic mass with hemorrhagic fluid and a variable amount of enhancing solid component, which can mimic mucinous borderline neoplasms [ 35 , 109 ]. However, decidualized nodules are usually smaller, with signal intensity similar to that of normal placenta, demonstrating higher signal intensity on T2-weighted images and no restricted diffusion on DWI compared to ovarian cancers [ 110 ].…”

“…Other conditions that can mimic malignancy at imaging are decidualized endometriomas and leiomyomas with red degeneration. Decidualized endometriomas are the result of progesterone action and increased glandular endometrial secretion and are characterized by increased blood flow and intraluminal papillary projections [ 35 ]. Red degeneration is a subtype of hemorrhagic infarction of leiomyomas that often occurs during pregnancy due to venous thrombosis within the periphery of the mass or rupture of intra-tumoral arteries [ 36 ].…”