Navigating Diagnostic Challenges: Heterotopic Pregnancy Versus Hyperdecidual Reaction in Ectopic Gestation

In the intricate field of obstetrics and gynecology, few scenarios present as complex a diagnostic challenge as the differentiation between heterotopic pregnancy, hyperdecidual reaction, and ectopic pregnancy. These conditions, while distinct, often blur together in clinical presentation, necessitating a nuanced understanding to achieve accurate diagnosis and timely intervention. A heterotopic pregnancy is a rare and potentially life-threatening condition in which a woman simultaneously carries two pregnancies in different locations. One pregnancy is typically located within the uterus (an intrauterine pregnancy), while the other is located outside the uterus, most commonly in one of the fallopian tubes (an ectopic pregnancy). This condition is sometimes referred to as a combined intrauterine and extrauterine pregnancy. The diagnosis of heterotopic pregnancy can be challenging because the symptoms can mimic those of a normal intrauterine pregnancy or an ectopic pregnancy. A combination of clinical symptoms, physical examination, and imaging studies, such as transvaginal ultrasound, can help in the diagnosis. After surgical or medical treatment, close monitoring and follow-up with a healthcare provider are essential. The remaining intrauterine pregnancy will need careful observation to ensure it continues to develop normally. However, in some cases of ectopic pregnancy, there will be hyperdecidual reaction within the uterus, which may sometimes create confusion with intrauterine pregnancy. Here, a case of ectopic pregnancy that was radiologically misdiagnosed as heterotopic pregnancy is presented to highlight the possibility of ectopic pregnancies being misdiagnosed as heterotopic pregnancy due to the hyperdecidual reaction. The index case underwent laparoscopic salpingectomy for tubal ectopic and dilatation and evacuation for suspected failed intrauterine pregnancy. The histopathological report of the intrauterine products of conception confirmed it to be decidua without any trophoblastic tissue.