Multimodality imaging techniques of diaphragmatic ectopic pregnancy: a case report and review of the literature.

A 39-year-old married Han Chinese female (gravida 2, para 1) presented to the Affiliated Jiangning Hospital of Nanjing Medical University in Nanjing, Jiangsu, China, on 29 September 2023 with a chief complaint of intermittent abdominal pain that occurred during inspiration. She had a history of one uncomplicated pregnancy and vaginal delivery. A total of 3 years prior to admission, she underwent in vitro fertilization (IVF), but the pregnancy ended in spontaneous abortion at approximately 12 weeks’ gestation, followed by a dilation and curettage (D&C). The patient reported that she had not experienced any discomfort until 24 h prior to her arrival at the hospital, at which point she began experiencing acute abdominal pain radiating to her right back. She noted a significant exacerbation of symptoms approximately 30 min before presenting to the emergency department. The patient did not report any accompanying symptoms such as gastrointestinal, urinary, or systemic symptoms. On evaluation in the emergency room, her vital signs were as follows: heart rate of 85 beats per minute, noninvasive blood pressure of 121/74 mmHg, respiratory rate of 22 breaths per minute, and oxygen saturation of 98% on ambient air. The patient had a regular 30-day menstrual cycle, and the last menstrual cycle was 18 days before the onset of the patient’s symptoms, which was similar to the patient’s other cycles in terms of bleeding amount and duration. The patient did not use contraception owing to her desire to become pregnant. Her past medical history was unremarkable. She had no history of intrauterine device (IUD) use and had not experienced pelvic inflammatory disease or any pelvic surgeries. Furthermore, there were no reported allergies or chronic conditions that could have contributed to her current symptoms. On physical examination, the patient exhibited tenderness in the right upper quadrant of the abdomen, and Murphy’s sign was positive. No rebound tenderness, rigidity, or palpable masses were noted. While in the emergency room, an initial CT scan of the abdomen and pelvis was completed 45 min prior to admission during the emergency resuscitation period. This decision was based on the clinical suspicion of a non-pregnancy-related acute abdominal condition, such as appendicitis or diverticulitis. Given the limitations of ultrasound in visualizing deep intraabdominal structures—including interference from bowel gas, limited field of view, and operator dependence—CT was selected as the preferred initial imaging modality for its superior diagnostic accuracy. This scan revealed pelvic effusion (mixed and hyperintense density, Fig.  1 a) with an approximately circular low-density area measuring 8.8 mm × 8.6 mm within the hematoma, initially interpreted as a subcapsular liver hematoma. Subsequent imaging and clinical evaluation suggested further investigation was needed. The patient was admitted to the emergency intensive care unit (EICU), where her hemoglobin level was 133 g/L (reference range: 115–150 g/L). Upon admission, the patient reported severe right upper quadrant pain with a pain score of 5/10. She also experienced intermittent episodes of nausea but no vomiting. Vital signs at admission were as follows: blood pressure 118/83 mmHg, heart rate 82 bpm, respiratory rate 19 breaths per minute, and temperature 36.6 °C. A transvaginal ultrasound (TVS) showed no intrauterine pregnancy, and an abdominal ultrasound revealed a subcapsular hematoma in the right lobe of the liver and free fluid in the abdominal and pelvic cavities, likely due to recent subcapsular bleeding. Fig. 1 X-ray computed tomography. a Initial computed tomography scan: slightly increased density merging with liver; clear boundary. An 8.8 mm × 8.6 mm decreased density area (black arrow) near the edge. b Enhanced computed tomography scan: slight increase in density around the circular periphery (white arrow) X-ray computed tomography. a Initial computed tomography scan: slightly increased density merging with liver; clear boundary. An 8.8 mm × 8.6 mm decreased density area (black arrow) near the edge. b Enhanced computed tomography scan: slight increase in density around the circular periphery (white arrow) During the first 48 h, the patient was closely monitored. Her pain fluctuated between two and four on the pain scale despite administration of analgesics. Abdominal examination revealed tenderness in the right upper quadrant without rebound tenderness. No palpable masses were detected. The patient’s hemoglobin level dropped from 133 to 118 g/L within 4 h postadmission and further decreased to 109 g/L approximately 24 h later. At this point, her serum blood human chorionic gonadotropin (β-hCG) level was significantly elevated at 2244 mIU/mL (reference range: 0–20 mIU/mL), suggesting a possible ectopic pregnancy or other conditions associated with elevated β-hCG levels. Given the declining hemoglobin levels, a contrast-enhanced CT scan was performed 24 h after the initial CT. This revealed a slight increase in density along the periphery of the circular area near the diaphragm (Fig.  1 b) and thickening of part of the diaphragm without ring-like enhancement. The liver exhibited compressive changes but maintained intact edges without significant thickening or enhancement. Her repeat β-hCG at 48 h had increased to 3166 mIU/mL. Her progesterone level was 10.20 ng/mL. Hemoglobin levels decreased from an initial value to 97 g/L by 48 h, indicating ongoing blood loss. This significant drop in hemoglobin suggested active hemorrhage, necessitating immediate further investigation and intervention. Additional imaging studies were ordered to identify the source of bleeding. Approximately 72 h after admission, due to the patient’s ongoing decline in hemoglobin levels, a multidisciplinary consultation was convened involving the general surgery, obstetrics and gynecology, and radiology departments. On the basis of this consultation, it was decided to perform a MRI scan. The MRI revealed a mixed signal area beneath the capsule of the right hepatic lobe. Specifically, T2-weighted imaging (T2WI) predominantly showed hypointense signals (Fig.  2 a), while T1-weighted imaging (T1WI) displayed striped hyperintense areas (Fig.  2 c). Within this mixed signal, a quasicircular structure measuring approximately 20 mm in diameter was identified, showing hyperintensity on T2WI and hypointensity with adjacent hyperintense patches on T1WI. On coronal views, the lesion appeared close to the diaphragm but distal to the liver parenchyma (Fig.  2 b). The MRI also demonstrated that the liver had relatively intact margins with signs of compression. Diffusion-weighted imaging (DWI) indicated hypointensity without any hyperintense regions (Fig.  2 d). Fig. 2 Magnetic resonance imaging. a T2-weighted imaging (horizontal): mixed signal under the right liver lobe capsule (*), mainly hypointense. A 20-mm quasicircular hyperintense signal (white arrow). b T2-weighted imaging (coronal): mixed signal under the right liver lobe capsule (*). A 20-mm quasicircular hyperintense signal (white arrow). c T1-weighted imaging: mixed signal under the right liver lobe capsule (*), with striped hyperintense areas. A 20-mm quasicircular hypointense area with adjacent hyperintense area (white arrow). d Diffusion-weighted imaging: hypointense signal under the right liver lobe capsule (*) Magnetic resonance imaging. a T2-weighted imaging (horizontal): mixed signal under the right liver lobe capsule (*), mainly hypointense. A 20-mm quasicircular hyperintense signal (white arrow). b T2-weighted imaging (coronal): mixed signal under the right liver lobe capsule (*). A 20-mm quasicircular hyperintense signal (white arrow). c T1-weighted imaging: mixed signal under the right liver lobe capsule (*), with striped hyperintense areas. A 20-mm quasicircular hypointense area with adjacent hyperintense area (white arrow). d Diffusion-weighted imaging: hypointense signal under the right liver lobe capsule (*) In summary, MRI findings indicated that the lesion was likely an ectopic pregnancy, with a high likelihood of it being a diaphragmatic pregnancy. Due to close monitoring and active fluid resuscitation support treatment after admission, the patient’s vital signs remained stable. However, given her progressively declining hemoglobin levels postadmission and relatively high β-hCG levels, methotrexate treatment was deemed inappropriate. Methotrexate is typically considered in cases of ectopic pregnancy when surgery is to be avoided and the patient meets specific criteria, such as hemodynamic stability and low β-hCG levels. After further multidisciplinary consultation and thorough discussions with the patient and her family, and considering the potential risks associated with methotrexate treatment, the decision was made to proceed with laparoscopic surgery. During the surgery, after evacuating the hematocele, the exposed surface of the liver appeared smooth with no evidence of subcapsular hematoma. A blood clot was observed between the liver and the diaphragm (Fig.  3 a). Histological examination confirmed the clot to be a mixture of chorion and blood (Fig.  3 d). The site of chorionic implantation was ultimately identified on the diaphragm (Fig.  3 b). The surgical procedure successfully removed the clot (Fig.  3 c). Fig. 3 Intraoperative imaging and pathology. a Laparoscopic view: blood clot with chorion (white arrow). b Post-clot removal: implantation site (white arrow) after clot removal. c Hemostasis: implantation sites (white arrow) after hemostasis using a radio knife burn. d Histologic section: chorionic villi from the diaphragm (hematoxylin and eosin stain, original magnification 100×) Intraoperative imaging and pathology. a Laparoscopic view: blood clot with chorion (white arrow). b Post-clot removal: implantation site (white arrow) after clot removal. c Hemostasis: implantation sites (white arrow) after hemostasis using a radio knife burn. d Histologic section: chorionic villi from the diaphragm (hematoxylin and eosin stain, original magnification 100×) The patient had already demonstrated a decline in hemoglobin levels preoperatively. During laparoscopic surgery, a large amount of bloody ascites and clots were identified within the abdominal cavity. In addition, approximately 200 mL of intraoperative blood loss was estimated. To maintain adequate oxygen delivery and hemodynamic stability, the patient received 400 mL of packed red blood cells intraoperatively. Postoperatively, minimal bloody drainage was observed from the abdominal drain, likely due to oozing at the surgical site. Conservative management with hemostatic therapy led to complete resolution of the drainage by postoperative day 6, at which time the drain was removed. Given the need for close monitoring following major surgery and blood transfusion, the patient remained hospitalized until postoperative day 7, when she was discharged safely. Within 24 h after surgery, her β-hCG level decreased to 521.0 mIU/mL, and her hemoglobin level increased to 106 g/L, further improving to 118 g/L. A total of 10 days after discharge, her β-hCG level had declined further to 9.3 mIU/mL, and the patient reported feeling well without any discomfort.

Ectopic pregnancy refers to the fertilized egg implanting outside the uterine cavity, which carries significant morbidity and mortality risks [ 1 ]. Approximately 95% of ectopic pregnancies occur in the fallopian tubes [ 2 , 3 ]. In contrast, abdominal pregnancies are rare, accounting for only about 1% of all ectopic pregnancies [ 4 ]. Abdominal ectopic pregnancies more commonly involve locations such as Douglas pouch, omentum, large vessels, and organs including the liver, spleen, and bowel [ 3 , 5 – 13 ]. Only a few cases of diaphragmatic ectopic pregnancy have been reported in PubMed [ 14 – 17 ]. We present a brief review of literature on this rare condition. Ectopic pregnancies are associated with high rates of intraperitoneal bleeding and mortality due to diagnostic challenges posed by atypical symptoms and signs [ 1 , 18 ]. Therefore, early diagnosis with multimodality imaging techniques is particularly crucial. Herein, we report a rare case of an ectopic pregnancy implanted on the diaphragm’s surface, which was diagnosed at the Affiliated Jiangning Hospital of Nanjing Medical University in Nanjing, Jiangsu, China. The patient was admitted on 29 September 2023, and underwent multimodality imaging techniques, including ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). We aim to provide insights and references for the diagnosis and management of similar rare cases in clinical practice.

We described an extremely rare case of diaphragmatic ectopic pregnancy diagnosed by using multimodality imaging techniques prior to treatment. This case underscores the diagnostic challenges posed by such atypical presentations. Utilizing multimodality imaging techniques before treatment is particularly significant for patients with ectopic pregnancy exhibiting abnormal clinical manifestations. These techniques enable the clear delineation of tissue planes, facilitating accurate diagnosis and preoperative planning by the surgical team.

Ectopic pregnancy refers to the abnormal pregnancy process in which a fertilized egg is implanted and developed outside the uterine cavity. This condition is relatively rare, accounting for only 1.3–2.4% of all pregnancies [ 1 ]. Nearly all ectopic pregnancies (95%) are tubal pregnancies, with even rarer occurrences in the cervix, ovaries, and abdominal cavity [ 2 ]. Less than 1% of ectopic pregnancies implant within the abdominal cavity [ 19 ]. Although the exact mechanism remains unclear, risk factors for ectopic pregnancy include tubal infections, surgeries, smoking, assisted reproduction, pelvic inflammatory disease, endometriosis, multiparity, and unknown causes [ 13 , 20 ]. A history of IVF treatment and curettage increases the risk of ectopic pregnancy. Diaphragmatic ectopic pregnancy is exceedingly rarer among these already uncommon cases, and its pathogenesis remains poorly understood. Most abdominal ectopic pregnancies implant in highly vascularized organs, which the diaphragm typically is not, making diaphragmatic implantation particularly unusual. Therefore, it takes great effort to say decisively that ectopic pregnancy on the diaphragm was the cause. Symptoms of abdominal pregnancy are often nonspecific, including abdominal pain or suprapubic pain, vaginal bleeding, and fetal movement pain [ 14 , 17 ], though diaphragm ectopic pregnancy may not show the above symptoms. Clinical diagnosis of diaphragmatic ectopic pregnancy is challenging due to vague and variable symptoms and clinical findings. In this case, the patient presented with right upper quadrant pain alone, complicating accurate diagnosis. Previous reports indicate that diaphragmatic ectopic pregnancy is especially difficult to diagnose and locate, with definitive diagnoses usually made intraoperatively or postoperatively. Chen’s review of 17 cases showed that the rate of preoperative diagnosis remained low, with only 29.41% of cases diagnosed preoperatively [ 21 ]. Abdominal ectopic pregnancy carries high morbidity and mortality risks due to potential complications such asplacental implantation site bleeding [ 10 , 11 , 22 ]. As a consequence, early diagnosis and timely individualized intervention are crucial for improving outcomes. Imaging plays a critical role in diagnosis of such conditions. With the advancement of diagnostic imaging technology, it has become routine to utilize imaging for disease diagnosis. Imaging techniques such as US, CT, and MRI are instrumental in achieving accurate diagnoses [ 23 ]. For women of childbearing age presenting with abnormal pregnancies and elevated β-hCG levels, employing multimodality imaging techniques is essential. Therefore, an overview of the commonly used technologies in current diagnostic practices is provided below. US is now the primary screening modality for ectopic pregnancy, enabling visualization of the anatomical position of the gestational sac and assessment of fetal activity, location, age, and placental position [ 23 ]. Color Doppler imaging can help determine the vascularity of any identified masses. If a transvaginal pelvic US raises suspicion of an ectopic pregnancy, an abdominal US should be performed to locate the potential abdominal implantation site. US not only detects the gestational sac but also offers a safe and convenient option for patients [ 24 , 25 ]. The most specific criterion for diagnosing ectopic pregnancy via US is the presence of an extrauterine gestational sac containing either a yolk sac or an embryo, with a specificity of 100% [ 26 ]. However, due to factors such as abdominal fat and intestinal gas, the sensitivity of this criterion is only 26% [ 27 , 28 ]. Additionally, while US is a targeted and useful diagnostic tool, atypia implantation sites may sometimes be overlooked. Therefore, in some cases, US alone cannot definitively exclude an ectopic pregnancy. Compared with US, multidetector CT and MRI can provide detailed regional anatomy and identify an ectopic gestational sac when US fails to do so [ 23 , 26 , 29 ]. In emergency radiology, multidetector CT is a valuable tool for diagnosing and managing acute abdominal pain in women. Contrast-enhanced CT can detect lesions by distinguishing differences in density [ 15 , 23 , 30 ]. MRI is particularly effective for diagnosing ectopic pregnancy, with a high detection rate of extrauterine gestational sacs [ 26 , 31 ]. DWI is especially useful for identifying ectopic pregnancies, as it shows a ring-like or dot-like high signal intensity within the gestational sac [ 26 ]. Contrast-enhanced MRI also aids in diagnosis by highlighting enhancement within the gestational sac [ 26 , 31 ]. Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) can accurately locate the gestational sac and implantation sites based on metabolic activity [ 32 , 33 ]. This modality provides additional diagnostic accuracy in suspected cases. Both MRI and CT are essential tools for planning subsequent treatments in such cases. Familiarity with the MRI and CT manifestations of ectopic pregnancy enables prompt and accurate diagnosis [ 34 ]. In our case, a TVS was performed and showed no evidence of intrauterine pregnancy. An abdominal ultrasound indicated a subcapsular hematoma in the right lobe of the liver and a small amount of fluid accumulation in the abdominal and pelvic cavities. However, due to intestinal gas, the imaging was unclear, complicating accurate diagnosis and preventing us from determining the characteristics and exact anatomical location of the lesion. The initial CT scan of abdomen and pelvic revealed mixed and hyperintense density between the liver and diaphragm. A nearly circular low-density area measuring 8.8 mm × 8.6 mm was observed within this region, but the imaging was not sensitive enough to precisely located the lesion or facilitate timely diagnosis. The contrast-enhanced CT scan and MRI subsequently identified a gestational sac-like mass without ring-like heterogeneous enhancement. This finding may be attributed to the lack of vascularization in the diaphragm and early-stage embryonic arrest. Contrast-enhanced CT scans demonstrated that the gestational sac-like mass was located near the diaphragm rather than the liver, with a thickening of part of the diaphragm noted. On MRI, the site of hemorrhage appeared spindle-shaped rather than crescent-shaped. The liver exhibited compressive changes with intact edges and no significant thickening or enhancement. MRI also confirmed that the lesion was distant from the liver, which had relatively intact margins. These findings were inconsistent with recent reports of hepatic ectopic pregnancies [ 23 , 30 , 33 , 35 ]. Therefore, we concluded that the gestational sac’s implantation site was on the diaphragm rather than the liver. Due to the limited vascularization of the diaphragm, rupture and bleeding occurred in the early stages of the gestational sac. However, the bleeding was not substantial enough to cause hemorrhagic shock, allowing the patient to remain hemodynamically stable throughout. The treatment options for ectopic pregnancy include surgery (laparoscopy or laparotomy), pharmacotherapy (methotrexate or intracardiac administration of potassium chloride), or a combination of both [ 13 ]. Qian et al . [ 15 ] reported a case where diaphragmatic ectopic pregnancy was successfully treated using ultrasound-guided percutaneous microwave ablation. Chen et al . [ 16 ] described the management of diaphragmatic pregnancy via laparoscopic intervention. Once an ectopic pregnancy ruptures, it can become life-threatening, often necessitating surgical intervention. In conclusion, the integration of multiple imaging modalities can aid in the diagnosis of complex cases and is beneficial for selecting optimal therapeutic approach and surgical technique. This comprehensive diagnostic approach ensures that even challenging cases, such as diaphragmatic ectopic pregnancies, can be accurately diagnosed and effectively managed.