Retained products of conception masquerading as acquired arteriovenous malformation

The accuracy of ultrasound scan in diagnosing retained products of conception: a systematic review and meta-analysis

OBJECTIVE

This study aimed to analyze and summarize the evidence on the accuracy of different ultrasound methods in the diagnosis of retained products of conception.

DATA SOURCES

We searched Ovid SP, the Cumulative Register to Nursing & Allied Health Literature, EBSCO, and grey literature including Core, Trip, Networked Digital Library of Theses and Dissertations Global ETD search, BMJ Best Practice, PubMed, GreyLit report website (http://www.greylit.org/), Cochrane Central Register of Controlled Trials, and Google scholar (https://scholar.google.com/).

STUDY ELIGIBILITY CRITERIA

We included prospective and retrospective cross-sectional or Cohort studies that evaluated both ultrasound findings (before management of retained products of conception) and histopathologic results of retained products of conception at all gestational ages.

METHODS

We used Covidence for data extraction from the studies and quality assessment. The meta-analysis was performed using RevMan 5.4 (forest plot), MetaDTA version 2.01, and Meta-DiSc 2.0 online software.

RESULTS

In total, 11 studies were eligible for data extraction and meta-analysis. The total number of study participants from these 11 studies were 1567. Of these, 9 studies were included to test the accuracy of an echogenic mass, 4 studies analyzed the accuracy of endometrial thickness, and 5 studies analyzed the accuracy of color Doppler flow to predict retained products of conception. We found that echogenic mass had the highest sensitivity, specificity, and diagnostic odds ratio for predicting retained products of conception. The sensitivity, specificity, and diagnostic odds ratio were 0.915 (95% confidence interval, 0.844-0.955), 0.843 (95% confidence interval, 0.615-0.947), and 57.787 (95% confidence interval, 15.171-220.112), respectively. The diagnostic threshold for endometrial thickness was set at 10 mm with a sensitivity, specificity, and diagnostic odds ratio of 0.667 (95% confidence interval, 0.072-0.981), 0.866 (95% confidence interval, 0.375-0.986), and 12.927 (95% confidence interval, 0.23-726.582). The sensitivity, specificity, and diagnostic odds ratio of color Doppler flow were 0.850 (95% confidence interval, 0.756-0.913), 0.406 (95% confidence interval, 0.198-0.655), and 3.893 (95% confidence interval, 1.005-15.081).

CONCLUSION

Our review concluded that an echogenic mass is the most sensitive and specific predictor of retained products of conception after any pregnancy event. The most important limitation of our review is that the design of the studies included led to significant statistical heterogeneity.

Trans-arterial embolization for intractable primary postpartum hemorrhage caused by arterial aneurysms with arteriovenous fistulas in the lower vagina bilaterally: a case report

Failure of conservative management for controlling postpartum hemorrhage (PPH) is not uncommon, particularly when PPH is caused by vascular lesions. Awareness of this possibility and initiating timely trans-arterial embolization (TAE) are essential for improving the outcome. Herein, we describe the case of a 34-year-old woman presenting with arterial aneurysms with arteriovenous fistulas in the lower vagina bilaterally, which caused intractable PPH. Conservative management failed to resolve the PPH; however, TAE successfully controlled the bleeding, and the patient recovered smoothly. Knowledge of this possible etiology for intractable PPH is crucial for timely TAE. This case report aims to highlight the pivotal role of TAE in detecting and treating this unusual cause of PPH.

Retained Placenta Percreta with Acquired Uterine Arteriovenous Malformation—Case Report and Short Review of the Literature

Placenta accreta spectrum disorder (PAS) has an increased frequency due to the high number of cesarean sections. The abnormal placentation associated with a retained placenta can cause persistent uterine bleeding, with ultrasound Doppler examination being the main choice to assess the uterine hemorrhage. An acquired uterine arteriovenous malformation (AVM) may occur because of uterine trauma, spontaneous abortion, dilation and curettage, endometrial carcinoma or gestational trophoblastic disease. The treatment for abnormal placentation associated with AVM can be conservative, represented by methotrexate therapy, arterial embolization, uterine curettage, hysteroscopic loop resection or radical, which takes into consideration total hysterectomy. Therapeutic management always considers the degree of placental invasion, the patient hemodynamic state and fertility preservation. Considering the aspects described, we present a case of retained placenta percreta associated with acquired uterine AVM, with imagistic and clinical features suggestive of a gestational trophoblastic disease, successfully treated by hysterectomy, along with a small review of the literature, as only a few publications have reported a similar association of diagnostics and therapy.

Color Doppler Imaging of Vascular Abnormalities of the Uterus

ABSTRACT

Many uterine abnormalities present clinically with bleeding encompassing a broad spectrum of patients from postmenopausal spotting to life-threatening hemorrhage. Color and spectral Doppler imaging of the pelvis is often the first crucial investigation used to quickly establish the correct etiology of the uterine bleeding and guide clinical decision making and patient management.

Placental polyp with arteriovenous malformation treated with a gonadotoropin-releasing hormone antagonist

A 35-year-old woman (gravida 1, para 0) underwent termination of pregnancy (ToP) at 12 weeks of gestation. One month after ToP, she experienced significant vaginal bleeding and the mass with blood flow was identified on imaging. The presence of a placental polyp with arteriovenous malformation (AVM) was suspected on transvaginal sonography and MRI. Since the bleeding had ceased when she visited our hospital, we decided to treat the placental polyp with AVM with gonadotropin-releasing hormone (GnRH) antagonist therapy instead of surgery. Two months after GnRH antagonist treatment, the mass and blood flow in the uterus disappeared. Menstruation resumed 1 month after the completion of treatment. In our case, we were able to successfully treat placental polyps with AVM using GnRH antagonist therapy.

Identifying the deceiver: the non-neoplastic mimickers of genital system neoplasms

Tumors of the genital system are common and imaging is of crucial importance for their detection and diagnosis. Several non-neoplastic diseases may mimic these tumors and differential diagnosis may be difficult in certain cases. Misdiagnosing non-neoplastic diseases as tumor may prompt unnecessary medical treatment or surgical interventions. In this article, we aimed to present the imaging characteristics of non-neoplastic diseases of the male and female genital systems that may mimic neoplastic processes. Increasing awareness of the imaging specialists to these entities may have a severe positive impact on the management of these patients.

Extreme enhanced myometrial vascularity following cesarean scar pregnancy: a new diagnostic entity

OBJECTIVE

To define, illustrate and to follow-up the diagnosis, pathophysiology and treatment of a subset of the known enhanced myometrial vascularity (EMV): its extreme form, associated with cesarean scar pregnancies (CSP) and with some cases pf placenta accreta spectrum being at increased risk of significant bleeding complications. We also aim to provide guidance to the management of such cases.

MATERIAL AND METHODS

This is an IRB-approved retrospective observational study of thirteen patients with an extreme form of EMV complicating CSPs. Patient's age, parity, number of cesarean deliveries, initial and time to negative serum hCG levels, primary and secondary diagnoses, blood flow peak systolic velocities, primary and secondary treatments, uterine artery embolization and outcomes were recorded.

RESULTS

Gestational ages ranged 6-11 weeks at initial presentation. Initial serum hCG was 20.0-102.48 mIU/L (mean 44.4 mIU/L). Diameter of EMV reached 20-75 mm (mean 46.8 mm). The mean peak systolic velocity (PSV) was 84.2 cm/s (range 46.7-118.0). Primary treatments were: systemic methotrexate (MTX) alone; D&C alone; MTX and D&C; local and systemic intra-gestational MTX injection; double cervical ripening balloon with systemic MTX; misoprostol and D&C; emergent UAE. UAE and hysterectomy were the two main secondary treatments in 10 women except 1 having a D&C after UAE, and in 1 the lesion regressed without secondary treatment. Mean time to nonpregnant hCG levels was 21-122 days (mean 67.2). Mean follow-up was 110.2 days (range 26-160). Ten women were treated with UAE, 6 had one, 3 had two embolizations. Two women had hysterectomies, one of these for persistent bleeding. Based upon the common denominators of the clinical and the US pictures, our definition of extreme EMV is sustained form of EMV associated with treated or untreated CSP, with peak systolic velocities of blood flow over 50 cm/s, slow return or plateauing serum hCG, with or without clinically significant vaginal bleeding, unresponsive to initial or secondary treatment requiring uterine artery embolization or hysterectomy.

CONCLUSION

The EMV developing in the background of retained placental tissue associated with CSP differs following the normal regression of the physiologically re-modelled, dilated vascular bed from the faulty "disrepair" of the vessel wall in in treated or untreated CSPs. The "threatening" appearance of the above EMVs warranted the term "extreme", creating their separate new sub-category." Extreme forms of CSP-related EMV pose significant diagnostic and management challenges. Prompt recognition and intervention, the proactive use of UAE, can maximize the outcome of women affected by this "extreme" form of EMV enabling to preserve reproductive potential. Obstetricians, gynecologists and interventional radiologists should be aware of this form of severe vascular complication.

Overview of Neo-Vascular Lesions after Delivery or Miscarriage

The concept of intrauterine neo-vascular lesions after pregnancy, initially called placental polyps, has changed gradually. Now, based on diagnostic imaging, such lesions are defined as retained products of conception (RPOC) with vascularization. The lesions appear after delivery or miscarriage, and they are accompanied by frequent abundant vascularization in the myometrium attached to the remnant. Many of these vascular lesions have been reported to resolve spontaneously within a few months. Acquired arteriovenous malformations (AVMs) must be considered in the differential diagnosis of RPOC with vascularization. AVMs are errors of morphogenesis. The lesions start to be constructed at the time of placenta formation. These lesions do not show spontaneous regression. Although these two lesions are recognized as neo-vascular lesions, neo-vascular lesions on imaging may represent conditions other than these two lesions (e.g., peritrophoblastic flow, uterine artery pseudoaneurysm, and villous-derived malignancies). Detecting vasculature at the placenta-myometrium interface and classifying vascular diseases according to hemodynamics in the remnant would facilitate the development of specific treatments.

Conservative management for retained products of conception after less than 22 weeks of gestation

AIM

The aim of the study was to investigate the efficacy of conservative treatment in cases of retained products of conception (RPOC) with a preceding pregnancy of less than 22 weeks and to assess whether serum beta-human chorionic gonadotropin (hCG) levels could be a useful index to monitor the progress of treatment.

METHODS

This is a case series of patients with RPOC developed after less than 22 weeks of gestation and managed expectantly with serial serum hCG measurement between 2011 and 2017. The clinical data of subjects were reviewed retrospectively. Cases that did not require invasive treatment such as surgery were designated as conservative management success.

RESULTS

A total of 19 cases were eligible: 14 miscarriages and 5 induced abortions. Eleven patients underwent dilatation and curettage. The diagnosis of RPOC was made 35 (8-80) days after abortion. All patients were successfully treated with conservative management. Serum hCG levels at diagnosis were 29.6 (3.2-1585) mIU/mL. Serial measurement of serum hCG was continued until the levels became lower than the cutoff value, and the mean duration to hCG disappearance was 67.5 (6-183) days. In all cases, RPOC vanished spontaneously 77 (27-184) days after diagnosis. The disappearance of RPOC in the uterine cavity was subsequent to a significant decrease in serum hCG. Once serum hCG levels reached the cutoff value, no bleeding episodes were observed.

CONCLUSION

Conservative management for RPOC might be acceptable and effective. Furthermore, serial serum hCG levels reflect the activity of RPOC, and hCG may be a reliable index to monitor the progress of treatment.

Hypervascular retained product of conception: Characteristic magnetic resonance imaging and possible relationship to placental polyp and pseudoaneurysm

The cases of two patients who developed myometrial vascularization following dilatation and curettage are described. In case 1, pathological diagnosis was possible with the resected specimens. This patient had hypervascular retained products of conception (RPOC). In case 2, the natural course of this pathological condition was observed, confirming a process of regression during repeated withdrawal bleeding. The three principal magnetic resonance imaging (MRI) findings in these cases were: (i) presence of a remnant; (ii) breaking of the junctional zone in contact with the remnant; and (iii) vascularization/flow voids infiltrating into the myometrium from the broken junctional zone. These three MRI findings differed in degree and varied in combination in each case of RPOC. Uterine artery pseudoaneurysms have been reported as intrauterine vascularization after abortion or delivery with subsequent spontaneous regression. These reports may include cases of hypervascular RPOC.

Unexpected Findings During Evaluation of Acute Pelvic Pain With Transvaginal Sonography

Transvaginal sonography is the first-line imaging modality used to evaluate acute female pelvic pain in the emergency setting because of its accessibility, lack of ionizing radiation, and excellent ability to identify reproductive tract disorders. Although the intent of transvaginal sonography is to evaluate the reproductive organs, imaging of adjacent pelvic structures is an important part of every transvaginal sonographic examination. Gastrointestinal, urologic, and vascular disorders incidentally scanned on transvaginal sonography may explain the pain for which the examination is being performed. In such cases, transvaginal sonography may play an important role in the diagnostic process if the clinician is aware of the transvaginal sonographic appearance of these entities.

Retained Placenta Accreta Mimicking Choriocarcinoma

This case demonstrates a rare event of retained invasive placenta masquerading as choriocarcinoma. The patient presented with heavy vaginal bleeding following vaginal delivery complicated by retained products of conception. Ultrasound and computed tomography demonstrated a vascular endometrial mass, invading the uterine wall and raising suspicion for choriocarcinoma. Hysterectomy revealed retained invasive placenta.

Ultrasonographic indications for conservative treatment in pregnancy-related uterine arteriovenous malformations

BACKGROUND

Uterine arteriovenous malformations (AVMs) are known to spontaneously regress.

PURPOSE

To assess the predictive value of ultrasonography for patients requiring conservative treatment for pregnancy related to AVMs.

MATERIAL AND METHODS

Our prospective study included 75 patients (conservative management:therapeutic management = 45:30) with vaginal bleeding from pregnancy-related AVM. Clinical and ultrasonography examinations were reviewed, and the following information was gathered: complete blood count, AVM maximal diameter, AVM echogenicity, retained product of conception, number of blood vessels, and spectral Doppler (pulsatility index [PI], resistance index [RI], peak systolic velocity [PSV], time-averaged maximum velocity [TAMXV]). The Doppler criteria by Timmerman (mean PSV >70 cm/s: therapeutic management, mean PSV < 52 cm/s: conservative management) were used for the initial management selection. The association between experimental variables and outcomes was assessed to determine their usefulness for predicting conservative management.

RESULTS

Features strongly associated with conservative management and their accuracy were PSV 89.6%, hemoglobin 84.7%, RI 83.1%, TAMXV 79.3%, and PI 78.6%. The overall accuracy for correct outcome classification was 64 (85.3%) of 75 patients. Most patients with conservative management had quicker improvement of symptoms and spontaneous regression at follow-up.

CONCLUSION

Ultrasonography can accurately predict selection of conservative management.

Hysteroscopic diagnosis and successful management of an acquired uterine arteriovenous malformation by percutaneous embolotherapy

Arteriovenous malformations are a rare but important cause of abnormal uterine bleeding in the midlife. Acquired uterine arteriovenous malformations are being increasingly diagnosed by transvaginal ultrasound, color Doppler and magnetic resonance angiography. We present a case where the suspected diagnosis was placental polyp or retained products of conception and hysteroscopy showed typical findings of uterine arteriovenous malformation, which was later, confirmed by magnetic resonance angiography. The patient underwent arterial embolization and recovered satisfactorily with resolution of hemorrhage and resumption of normal menstrual cycles. Abnormal bleeding due to arteriovenous malformations is worsened by curettage and hence its recognition is important in the management of abnormal uterine bleeding in the midlife.

[Case study of a severe hemorrhage during a dilatation and curettage: Arteriovenous malformation or first trimester placenta accreta?]

A 27-year-old woman had a uterine curettage that was complicated by a severe hemorrhage. Ultrasonography and MRI showed a vascular lesion of the uterine fundus suspected to be an atypical arteriovenous malformation. The lesion spontaneously disappeared 2months later. The two most likely diagnoses are an arteriovenous malformation or a placenta accreta. The aim is to discuss the etiology of this serious complication from a case report of a severe hemorrhage during a uterine curettage.

Retained products of conception: spectrum of color Doppler findings

OBJECTIVE

The purpose of this study was to characterize color Doppler imaging features of retained products of conception (RPOC) with gray scale correlation.

METHODS

Clinically suspected cases of RPOC between January 2005 and February 2008 were reviewed. Patient data and relevant color Doppler and gray scale features were recorded.

RESULTS

A total of 269 patients referred for sonographic evaluation for RPOC were identified. Thirty-five patients had confirmed pathologic diagnoses, 28 of whom had RPOC. In those with RPOC, 5 (18%) were avascular (type 0); 6 (21%) had minimal vascularity (type 1); 12 (43%) had moderate vascularity (type 2); and 5 (18%) had marked vascularity (type 3). Peak systolic velocities ranged from 10 to 108 cm/s (average, 36.1 cm/s). Resistive indices in arterial waveforms ranged from 0.33 to 0.7 (average, 0.5). Five (45%) of the patients with type 0 vascularity had RPOC; 6 (86%) of those with type 1 had RPOC; and 17 (100%) of those with types 2 and 3 had RPOC. An echogenic mass had a moderate positive predictive value (80%) but low sensitivity (29%) for RPOC.

CONCLUSIONS

Color Doppler evaluation of the endometrium is helpful in determining the presence of RPOC. Endometrial vascularity is highly correlated with RPOC, whereas the lack of vascularity can be seen in both intrauterine clots and avascular RPOC.

Postabortion Doppler evaluation of the uterus: incidence and causes of myometrial hypervascularity

OBJECTIVE

The aim of this study was to investigate the incidence and causes of uterine hypervascular lesions showing low-impedance, high-velocity flow on color Doppler sonography (CDS) after first-trimester dilation and curettage (D&C).

METHODS

This was a prospective study of 65 consecutive women who underwent first-trimester termination of pregnancy. Color Doppler sonography of the uterus was performed on days 3 and 10 after D&C. If the myometrial hypervascularity (MH) persisted on day 10, a second D&C was performed, and then the patients were followed with weekly Doppler examinations.

RESULTS

In 16 of 65 women (24.6%), MH was detected with CDS on day 3 after D&C. In 3 cases, MH resolved spontaneously by postabortion day 10. In the remaining 13 patients, the second D&C performed on day 10 revealed retained products of conception (RPOC) in 8 patients (61.5%), a hydatidiform mole in 2 (15.4%), endometritis in 1 (7.7%), and no abnormality in 2 (15.4%). Complete resolution of the MH occurred in all cases. The mean period to the resolution of MH after the second D&C +/- SD was 16.54 +/- 11.06 days (range, 7-48 days). Univariate analysis revealed that gestational age at D&C (P = .012) and a history of any uterine surgery (P = .044) were significantly associated with postabortion MH. On binary logistic regression analysis, gestational age at D&C was the only independent predictive factor for MH (P = .016; odds ratio, 1.47; 95% confidence interval, 1.08-2.02).

CONCLUSIONS

The presence of hypervascular areas within the myometrium is a common finding in the postabortion period, and in most cases, the cause of this finding is RPOC.

Computed tomographic angiography in diagnosis and management of placental polyp with neovascularization

OBJECTIVE

To evaluate the neovascularization in placental polyp tissue by computed tomographic angiography and to determine the need for uterine artery embolization before hysteroscopic resection.

STUDY DESIGN

Seventeen consecutive women with suspected placental polyp were enrolled in this retrospective study. Neovascularization in placental polyp tissue was assessed by computed tomographic angiography. Cases with neovascularization were treated by hysteroscopic resection with preoperative uterine artery embolization, while cases without neovascularization were treated by hysteroscopic resection alone.

RESULTS

Of 17 patients with suspected placental polyp after abortion or parturition, nine patients were diagnosed to have placental polyp with prominent neovascularization by computed tomographic angiography, and were treated by uterine artery embolization followed by hysteroscopic resection. Two patients subsequently conceived after conservative management.

CONCLUSIONS

After precise evaluation of neovascularization by computed tomographic angiography, hysteroscopic resection with preoperative uterine artery embolization is an effective minimally invasive procedure to conservatively treat placental polyp with prominent neovascularization.

Sonography of uterine abnormalities in postpartum and postabortion patients: a potential pitfall of interpretation

OBJECTIVE

The interpretation of postpartum and postabortion uterine abnormalities on sonography can be challenging. The purpose of this study was to identify misleading imaging features that lead to inclusion of a uterine arteriovenous malformation (AVM) in the differential diagnosis of a uterine abnormality because consideration of this diagnosis can potentially alter patient treatment.

METHODS

The sonographic examinations of 29 pathologically proven cases of uterine abnormalities in postpartum and postabortion patients were retrospectively reviewed. Two radiologists independently evaluated several features: the presence of a uterine mass, myometrial involvement, and the presence of an associated vascular abnormality. Percent agreement and the relationship between imaging features and inclusion of a uterine AVM in the differential diagnosis were determined.

RESULTS

Interobserver agreement was as follows: the presence of a uterine mass, 90%; myometrial involvement, 83%; the presence of an associated vascular abnormality, 72%; and inclusion of a uterine AVM in the differential diagnosis, 86%. Myometrial involvement showed a statistically significant relationship to inclusion of a uterine AVM in the differential diagnosis (P < .05). Final pathologic diagnoses included retained products of conception (RPOC) (n = 26), an endometrial polyp (n = 1), chronic endometritis (n = 1), and an exogenous progestational effect (n = 1). No uterine AVMs were found.

CONCLUSIONS

Despite high interobserver agreement in characterizing uterine abnormalities on sonography, readers still include uterine AVMs in the differential diagnosis of uterine masses that are ultimately proven to be RPOC. A myometrial location of a uterine mass is a particularly misleading imaging feature of RPOC.

MR Imaging of Benign Uterine Disease

MR provides excellent depiction of the female pelvic anatomy and has become the imaging modality of choice for the accurate diagnosis of numerous benign gynecologic conditions. Detection and characterization of leiomyomata and adenomyosis is performed routinely at many centers, and MR plays an important role in stratifying patients into appropriate treatment options. MR imaging is also uniquely well suited to the evaluation of gynecologic conditions that occur during pregnancy and in the postpartum period. This article describes MR protocols and the typical findings of various benign conditions of the uterine corpus and cervix, including congenital anomalies, leiomyomas, adenomyosis, and complications related to pregnancy.

Imaging of vascular disorders of the female pelvis

Clinical presentation of vascular disorders of female pelvis including placental adhesion, retained product of conception, ovarian venous thrombosis, varices, torsion and haemorrhagic infarct of ovary is often non-specific. Because of its availability, safety, and cost-effectiveness, ultrasound is the first investigation of choice. Computed tomography and MRI clearly depict the pelvic and retroperitoneal anatomy. This pictorial essay illustrates the complementary role of US, CT, and MRI in diagnosing vascular disorders of female pelvis.

Successful Pregnancy with a Full-Term Vaginal Delivery One Year After n-Butyl Cyanoacrylate Embolization of a Uterine Arteriovenous Malformation

Uterine arteriovenous malformation (AVM) causes significant morbidity with vaginal bleeding. Traditional therapy is a hysterectomy with no potential for future pregnancy. We present a case of successful superselective embolization of uterine AVM using n-butyl cyanoacrylate with subsequent normal term pregnancy and uncomplicated vaginal delivery in 1 year.

MR Imaging of Maternal Diseases of the Abdomen and Pelvis during Pregnancy and the Immediate Postpartum Period

Magnetic resonance (MR) imaging provides multiplanar large field-of-view images of the body with excellent soft-tissue contrast and without ionizing radiation. As a result, MR imaging is increasingly being used to image the maternal abdomen and pelvis during and immediately after pregnancy. Results of rapid T1- and T2-weighted imaging are often diagnostic, and blood vessels, ductal structures, and the urinary tract can frequently be visualized without intravenous administration of contrast material. Until more conclusive safety data become available, MR imaging should be reserved for cases in which results of ultrasonography are inconclusive and patient care depends on further imaging. In the setting of acute abdomen during pregnancy, MR imaging allows identification of areas of inflammation, abscess formation, hemorrhage, and bowel obstruction. MR imaging also helps determine the organ of origin, extent, and composition of maternal neoplasms and is useful in evaluation of müllerian duct anomalies and abnormalities of placental formation, position, and implantation. Many postpartum complications such as retained products of conception and uterine dehiscence may be diagnosed with MR imaging when results of other modalities are indeterminate.

Postpartum MR diagnosis of retained placenta accreta

Retained placenta accreta can cause catastrophic postpartum hemorrhage. This study aims to determine whether MR imaging can differentiate retained placenta accreta from postpartum hemorrhage caused by other conditions. Fourteen cases suspicious for retained placenta were examined with MR imaging. Signal intensity, the enhancing pattern of uterine contents, and flow voids within the myometrium were retrospectively studied. As hysterectomy was performed in only two cases, final diagnosis was based on clinical outcome and analysis of uterine contents. Final diagnoses were retained placenta accreta in seven cases, retained normally attached placenta in four, hematoma in two, and placental site trophoblastic tumor (PSTT) in one. All seven cases with placenta accreta had a very hyperintense area on T2-weighted images, showing transient early enhancement. None demonstrated delayed strong enhancement around the hyperintense area. In two cases with retained normally attached placenta and in both with hematomas, there were no hyperintense areas on T2-weighted images. Of these, only one showed transient early enhancement. Flow voids were observed in four cases with placenta accreta, one with normally attached placenta, and the case with PSTT. A markedly hyperintense area on T2-weighted images and transient early enhancement without delayed strong enhancement between the mass and the myometrium can indicate retained placenta accreta.

Diffusely enlarged uterus: evaluation with MR imaging

Diffuse uterine enlargement is a common clinical finding. Because this abnormality can represent a physiologic manifestation, benign tumor, or malignancy, the diagnostic dilemma of a diffusely enlarged uterus can be challenging. Clinical findings can provide valuable information in regard to physiologic effects, pregnancy-related changes, and hormonal causes. Cytologic examination is essential for identification of cervical and endometrial malignancies. However, since preoperative histologic examination of myometrial lesions is not possible, preoperative distinction between benign and malignant conditions is frequently difficult. Imaging thus plays an important role in evaluation of myometrial lesions. In particular, magnetic resonance (MR) imaging allows specific diagnosis of several different lesions. Signal voids and prominent vessels at MR imaging are characteristic of vascular lesions. Adenomyosis and leiomyomas can be distinguished from other lesions with MR imaging, although a variety of unusual manifestations can be seen. MR imaging findings that allow distinction between leiomyoma and leiomyosarcoma have yet to be clearly established; however, invasion, hemorrhagic necrosis, or rapid growth is suggestive of malignancy. Endometrial stromal sarcoma tends to have distinct MR imaging features that allow differentiation from benign lesions.