Heterotopic pregnancy: a case report of intrauterine hydatidiform mole with tubal pregnancy

Abstract

We herein report a rare case of simultaneous intrauterine molar pregnancy and tubal pregnancy. A woman of childbearing age who had never been pregnant underwent an ultrasound examination 70 days after the onset of menopause. She had a history of ovulation induction. The ultrasound findings suggested a partial hydatidiform mole. She was then pathologically confirmed to have a complete hydatidiform mole after uterine suction dilation and curettage. On postoperative day 4, an ultrasound examination before discharge showed an inhomogeneous mass in the left adnexal region with mild lower abdominal pain. On postoperative day 17, the blood human chorionic gonadotropin level did not drop as expected, and a follow-up examination still indicated a mass in the left adnexal region. We were unable to rule out an ectopic hydatidiform mole. Hysteroscopy with laparoscopic exploration of the left adnexal mass and salpingotomy suggested a diagnosis of intrauterine hydatidiform mole combined with left tubal pregnancy.

Introduction

Heterotopic pregnancy (HP) is an extremely rare pathological pregnancy in which both intrauterine and ectopic pregnancies are simultaneously present. With the development of assisted reproductive techniques, the incidence of HP has increased from 1 in 30,000 pregnancies to 1 in 3900 pregnancies. ¹ A hydatidiform mole is a benign gestational trophoblastic disease, and its incidence rates vary by geographic area. ² In Asia, the incidence of hydatidiform mole is approximately 1 in 500 pregnancies. ³ An intrauterine hydatidiform mole combined with an ectopic pregnancy is much rarer. High levels of serum human chorionic gonadotropin (hCG) in these patients can lead to atypical clinical symptoms. ⁴ Thus, early diagnosis and early treatment are challenging in these patients. We herein report a case involving a woman with an intrauterine hydatidiform mole and tubal pregnancy who was admitted to our hospital.

Case report

A woman in her early 30s was admitted to another hospital with a history of no menstruation for 71 days and a sensation of lower abdominal distention. This pregnancy had been assisted by ovulation-promoting drugs (details not specified). On day 35 of amenorrhea, her hCG level was measured at 24.6 mIU/mL. Her hCG level was subsequently monitored and gradually increased. On day 64 of amenorrhea, a pelvic ultrasound indicated that the uterine cavity appeared to contain a gestational sac with no echogenic area. On day 71 of amenorrhea, a repeat ultrasound showed an intrauterine cystic solid echo of approximately 5.8 × 2.8 cm, suggesting a partial hydatidiform mole. The uterus was enlarged to the size of a 3-month pregnancy, and suction evacuation was performed on the same day under ultrasound guidance. On the second postoperative day, her blood hCG level was rechecked and found to be 19,700.7 mIU/mL. The postoperative pathology report indicated a large number of highly edematous placental villi and trophoblast cells, highly edematous interstitial placental villi, and mild proliferation of trophoblast cells. Immunohistochemical staining showed inhibin-a (+), P57 (−), and Ki67 (80% +). Based on the morphology and immunohistochemical staining results, the diagnosis was considered a complete hydatidiform mole. Histopathological examination confirmed this diagnosis. The patient was then discharged.

On postoperative day 4, however, a heterogeneous echo pattern was found near the left ovary, and the patient experienced mild pain in the left lower abdomen. On postoperative day 17, her serum hCG level was 4532 mIU/mL, and ultrasound examination revealed a mass in the left adnexa (Figure 1(a), (b)). Considering the insignificant decrease in the serum hCG level and the possibility of an ectopic hydatidiform mole, hysteroscopy combined with laparoscopy was performed. During the operation, approximately 50 mL of hemoperitoneum was observed in the pelvis, and the left fallopian tube was found to be thickened to 3 × 2 × 2 cm on laparoscopic examination (Figure 1(c), (d)). Decidual-like tissues were observed in the posterior wall of the uterine cavity, and the left uterine horn exhibited tortuous, thickened vessels with a small amount of blood leakage. A small amount of decidual-like tissue was scraped from the posterior wall of the uterine cavity using a loop electrosurgical excision procedure. A laparoscopic salpingostomy was conducted on the left fallopian tube (Figure 1(e)). The serum hCG level was 974.2 mIU/mL on postoperative day 1 and 47.5 mIU/mL on postoperative day 7. The left fallopian tube pregnancy tissue along with clots and villi were sent for examination. The postoperative pathological report indicated that some of the villi had regressed, consistent with an ectopic pregnancy. The uterine cavity contents were degenerated, and necrotic tissue was considered to be uterine cavity residue (Figure 1(f)). The patient recovered well and was discharged for follow-up. The reporting of this study conforms to the CARE guidelines. ⁵

Figure 1.

Diagnostic imaging and surgical findings. (a) Pelvic ultrasound images. (b) Pelvic magnetic resonance images. (c, d) Findings of laparoscopic exploration. (e) Pregnancy tissue in the fallopian tube and (f) histopathological section of left tubal pregnancy (hematoxylin and eosin, 20×).

Discussion

We have herein reported an extremely rare case of an intrauterine hydatidiform mole with a left tubal pregnancy. HP is a rare type of natural pregnancy, but with the development of assisted reproductive techniques, the incidence of HP has been increasing. At present, the diagnosis of HP is mainly determined by clinical symptoms, signs, the serum hCG level, ultrasound examination, and laparoscopic exploration. Many patients with HP have no obvious clinical symptoms in the early stage. ⁶ When gynecological ultrasound fails to detect an ectopic pregnancy coexisting with an intrauterine pregnancy, HP becomes much more difficult to diagnose. The presence of an intrauterine pregnancy complicates the diagnosis of an ectopic pregnancy based on the serum hCG level alone. ⁷ The serum hCG level is higher in women with an intrauterine hydatidiform mole than in women with an intrauterine pregnancy, and a high serum hCG level is more likely to hide the presence of ectopic pregnancy. ⁸ Therefore, early diagnosis and early treatment of HP are challenging. In this case, ultrasound examination revealed a mass in the left adnexal region, and the patient developed mild abdominal pain on postoperative day 4. However, this was not adequately followed up, which was the main reason for the missed diagnosis of ectopic pregnancy in this patient. Fortunately, hysteroscopy combined with laparoscopy was performed when the serum hCG level did not significantly decrease after hydatidiform mole removal. This procedure confirmed the final diagnosis, and the patient was treated promptly before rupture. Our case reminds us that HP should be considered if the decrease in the serum hCG level is not significant after hydatidiform mole removal and ultrasound reveal suspicious extrauterine abnormalities. Moreover, in patients with an intrauterine hydatidiform mole, a mass in the adnexal region detected by ultrasound should not only be considered an ovarian cyst due to staphyloma; a possible ectopic pregnancy should also be considered. Further examinations such as pelvic magnetic resonance imaging or hysteroscopy are required, and laparoscopic exploration should be performed if necessary. Laparoscopic examination is the gold standard for the diagnosis of HP. ⁹ If the decrease in the serum hCG level is not significant after hydatidiform mole removal and ultrasound reveals suspicious extrauterine abnormalities, hysteroscopy combined with laparoscopic exploration is recommended as soon as possible to rule out an intrauterine residual hydatidiform mole and assist the diagnosis and treatment of HP.

Conclusion

With the increasing resolution of modern ultrasound instruments and the continuous improvement of ultrasound ancillary examination techniques, the diagnosis of a hydatidiform mole can be detected within 8 weeks of menopause, when the presence of ectopic pregnancy is often not easily detected. Our hospital experienced a case of a hydatidiform mole detected by ultrasound screening at only 38 days of menopause. Ultrasonography is the main tool for the diagnosis of ectopic pregnancy. In particular, clinicians have recognized the usefulness of transvaginal ultrasound in gynecology, and timely diagnosis and treatment of the patient in the present case were made possible by the clinical findings relayed by our ultrasonographers. However, some studies have shown that only 26.25% of patients can be diagnosed by ultrasonography before surgery; therefore, improving ultrasonographers’ skill level in diagnosis and treatment can help improve the diagnosis and treatment of this disease. ¹⁰ Laparoscopy is the gold standard for the diagnosis of ectopic and intrauterine compound pregnancy. If the serum hCG level does not significantly decrease after clinical clearance of a hydatidiform mole, and when ultrasound shows suspicious ectopic abnormalities, early combined hysteroscopic exploratory surgery is recommended to exclude intrauterine residual hydatidiform mole and to assist in the diagnosis and management of ectopic and intrauterine compound pregnancy.

Supplemental Material

sj-pdf-1-imr-10.1177_03000605241258572 - Supplemental material for Heterotopic pregnancy: a case report of intrauterine hydatidiform mole with tubal pregnancy

Supplemental material, sj-pdf-1-imr-10.1177_03000605241258572 for Heterotopic pregnancy: a case report of intrauterine hydatidiform mole with tubal pregnancy by Ruoxi Wang, Yiwei Zhang, Jun Liang, Yi Li and Jian Wang in Journal of International Medical Research