MR imaging of fetal sacrococcygeal teratoma: diagnosis and assessment

Congenital and gynecological tumors: A review

Congenital tumors are rare, and malignant congenital tumors are uncommon. Benign tu,mors might be life-threatening, depending on the location and size of the tumor. Different factors affect congenital tumors, such as maternal and placental hormones and environmental factors such as drugs, radiation, and infection. Developing fetal imaging methods and continuous follow-up during pregnancy are important factors in congenital tumor prognosis. Ultrasound is the most common method used for fetal evaluation. The complementary evaluation method is MRI. Both methods are helpful and widely spread for the detection of congenital tumors. These imaging methods help the medical team make a suitable decision about therapy. Some of these tumors regressed spontaneously, and some need surgical treatments. Treatment of tumors has developed rapidly, and recently molecular-targeted drugs have been used.

Magnetic resonance imaging of fetal abdominal pathology: a complementary tool to prenatal ultrasound

Fetal magnetic resonance imaging (MRI) is increasingly being used worldwide as a complementary tool to prenatal ultrasound (US) for multiple fetal pathologies. The aim of this article is to describe and illustrate how MRI can help US to evaluate fetal abdominal anomalies, based on cases performed in a tertiary public university hospital. Prenatal US, fetal MRI and postnatal imaging of these cases will be shown side-by-side to describe and illustrate the added value of fetal MRI in the different organs/systems and its impact on clinical management.

Fetal Sacrococcygeal Teratoma: A Case Report of a Giant Tumor withan Excellent Outcome

Sacrococcygeal teratoma (SCT) occurs in approximately 1 per 20,000-40,000 births and is the most frequently encountered fetal teratoma, with 75% of cases observed in female fetuses. SCT can be detected on ultrasound as early as the first trimester, presenting as a large mass originating from the sacrococcygeal area, with or without an intrapelvic component. The prenatal course for most fetuses with SCT is generally uneventful, with only a few cases experiencing obstetric and fetal complications. We present the case of a 19-year-old woman who was in good health and had no relevant family or medical history. She was gravida 2 and para 1. During the first trimester scan, an examination revealed a heterogeneous mass in the presacral area with a predominantly multicystic appearance, measuring 12 mm in diameter. At 21+6 weeks of gestation, the Type 2 fetal SCT showed an increase in volume with the size of 49×37×36 mm and contiune to increase in size. The male fetus was delivered by elective Cesarean section at 38 weeks of gestation. The resection of the tumor and coccyx was performed when the newborn was 7 days old. The tumor measured 190×160×100 mm and weighed 1100 g. Pathological examination confirmed the diagnosis of a mature teratoma (Grade 0), and the resection margins were negative. Our case report highlights a fetus with a large and rapidly growing SCT, yet the outcome was excellent.

Imaging of pediatric extragonadal pelvic soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

The most common pediatric extragonadal pelvic cancers include germ cell tumors, sacrococcygeal teratomas, and rhabdomyosarcomas (arising from the urinary bladder, prostate, paratesticular tissues, vagina, uterus, and perineum). This paper describes the radiological and nuclear medicine features of these entities and provides consensus-based recommendations for the assessment at diagnosis, during, and after treatment.

The ex-utero intrapartum treatment (EXIT) strategy for fetal giant sacrococcygeal teratoma with cardiac insufficiency: A case report and review of the literature

BACKGROUND

Antenatally diagnosed sacrococcygeal teratoma has been associated with risks of perinatal complications and death, especially when the foetus has symptoms of cardiac insufficiency, hydrops or anemia in utero; however, the method of intervention remains controversial.

CASE

A 25-year-old pregnant woman was found to have a cystic and solid tumor in the fetal sacrococcygeal region at 16 weeks of gestation. As the tumour grew, the mother developed polyhydramnios accompanied with gestational diabetes. Fetal and tumorous hemodynamics were closely monitored by ultrasound. Abnormal cardiac function was detected at 31 weeks' gestation, and we creatively performed pre-emptive delivery through the ex-utero intrapartum treatment with debulking. The teratoma was removed with utero-placental circulation support. The operation proceeded smoothly with favourable prognosis for both mother and newborn.

CONCLUSION

The ex-utero intrapartum treatment may improve the prognosis for fetuses with heart failure when they reach viable gestation.

Fat-containing pelvic lesions in females

Pelvic tumors are common in females and have a broad differential diagnosis. The clinical management of pelvic tumors varies widely-from observation to surgical resection-and imaging plays a pivotal role in diagnosis and clinical decision-making in these cases. In particular, imaging can help determine the organ of origin and tissue content of these tumors, which are the most important steps to narrowing the differential diagnosis. Fat has a characteristic appearance and is often easily identified on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). The amount and distribution of intralesional fat varies in different types of tumors. Macroscopic intralesional fat is often easily recognized by its hyperechoic appearance on US and low attenuation on CT similar to subcutaneous fat. On MRI, macroscopic fat is hyperintense on T1-weighted (T1W) images, with characteristic signal loss on fat-saturated sequences and India-ink artifact on opposed-phase T1W images. Macroscopic fat is the hallmark of teratomas, which are the most common ovarian neoplasms. Uterine lipoleiomyomas, peritoneal loose bodies, intraperitoneal and extraperitoneal primary lipomatous tumors such as lipoma and liposarcomas, and extra-adrenal myelolipomas are other pelvic masses distinguished by the presence of macroscopic fat. However, the imaging diagnosis of pelvic masses containing minimal or microscopic fat, such as immature ovarian teratomas, steroid cell ovarian neoplasms, and extramedullary hematopoiesis, can present a diagnostic challenge owing to their nonspecific appearance on US or CT. Obtaining MRI with in-phase and opposed-phase dual-echo T1W sequences and depicting chemical shift artifacts can be helpful in distinguishing these lesions.

Multimodality Imaging Evaluation of Fetal Spine Anomalies with Postnatal Correlation

Congenital anomalies of the spine are associated with substantial morbidity in the perinatal period and may affect the rest of the patient's life. Accurate early diagnosis of spinal abnormalities during fetal imaging allows prenatal, perinatal, and postnatal treatment planning, which can substantially affect functional outcomes. The most common and clinically relevant congenital anomalies of the spine fall into three broad categories: spinal dysraphism, segmentation and fusion anomalies of the vertebral column, and sacrococcygeal teratomas. Spinal dysraphism is further categorized into one of two subtypes: open spinal dysraphism and closed spinal dysraphism. The latter category is further subdivided into those with and without subcutaneous masses. Open spinal dysraphism is an emergency and must be closed at birth because of the risk of infection. In utero closure is also offered at some fetal centers. Sacrococcygeal teratomas are the most common fetal pelvic masses and the prognosis is variable. Finally, vertebral body anomalies are categorized into formation (butterfly and hemivertebrae) and segmentation (block vertebrae) anomalies. Although appropriate evaluation of the fetal spine begins with US, which is the initial screening modality of choice, MRI is increasingly important as a problem-solving tool, especially given the recent advances in fetal MRI, its availability, and the complexity of fetal interventions. Online supplemental material is available for this article. ^©RSNA, 2021.

Intramedullary cervical spinal cord teratoma

BACKGROUND

Intramedullary cervical spinal cord teratomas (ICTs) are extremely rare, and diagnosis and treatment are challenging. We conducted a systematic review of the literature on the diagnosis and treatment of ICT.

METHOD

The presentation, imaging manifestations, diagnosis, management, surgery findings, prognosis and histology were reviewed following Preferred Reporting Items for Systematic Reviews and Meta Analyses guidelines. English-language studies and case reports published from inception to 2018 were retrieved. Data on presentation, imaging characteristics, diagnosis, management, surgery findings, outcomes, and histopathology were extracted.

RESULTS

Ten articles involving 10 patients were selected. The lesions were located in the upper cervical vertebrae in 4 cases, whereas in the lower cervical vertebrae in the remaining 6 cases. In 5 cases, the lesions were located on the dorsal side of the spinal cord, and in the center of the spinal cord in the remaining 5 cases. Quadriparesis (60%), paraplegia (30%), monoplegia (10%), and neck pain (50%) were the main presentations. The lesion appeared as a intramedullary heterogeneous signal during an MRI scan, and the lesion signal would be partially enhanced after the contrast medium was applied. All patients underwent surgical intervention through a posterior approach. Neurological function improved postoperatively in all patients. Two patients with pathology confirmed to be immature teratomas experienced recurrence.

CONCLUSION

ICTs are extremely rare entities that are mainly located in the center or dorsal part of the spinal cord which mainly manifest as quadriplegia and neck pain. MRI is a useful modality that provides diagnostic clues. Surgery from a posterior approach is the primary treatment, and the effect of adjuvant therapy remains uncertain. The prognosis is mainly related to the pathological nature of the tumor and not the method of resection.

[Imaging of abdominal tumors in childhood and adolescence : Part II: relevant intra-abdominal and retroperitoneal tumor entities]

Abdominal and pelvic tumors in children and adolescents can be manifested intra-abdominally and also often in the retroperitoneum. The most important pediatric primary retroperitoneal space-occupying lesions are nephroblastoma (Wilms' tumor) and neuroblastoma, whereby imaging plays a decisive role in the diagnostics and differentiation of the two entities. Benign tumors of the mesentery and gastrointestinal tract occur more frequently in children than malignant lesions. The benign entities include lipoma, polyps and vascular tumors, such as lymphatic malformations. Of the malignant sarcomas, abdominal rhabdomyosarcomas (RMS) occur relatively often in childhood and adolescence. The most frequent pediatric abdominal lymphoma is Burkitt's lymphoma, an aggressive subtype of non-Hodgkin's lymphoma. Relevant tumor entities in childhood are also germ cell tumors, which originate from the genitals (gonadal) or can be extragonadally manifested. The benignancy or malignancy of germ cell tumors ranges from benign teratomas to highly malignant entities, such as yolk sac tumors. The germ cell tumors, just as all pediatric abdominal mass lesions, show a broad spectrum of tumor aggressiveness, malignancy and therefore also prognosis and mortality for the affected children and adolescents.

Radiological features of sacrococcygeal teratomas in fetal magnetic resonance imaging and computed tomography - a case report

Purpose

Sacrococcygeal teratomas (SCT) can be detected in ultrasonography as early as in the first trimester. Currently, prenatal ultrasonography enables a thorough examination of tumors, but it is not always sufficient. The purpose of this study was to determine the most important features of SCTs in fetal magnetic resonance imaging and to confront them with postnatal computed tomography (CT).

Case report

Between 2009 and 2013, 5 cases of sacrococcygeal teratomas were diagnosed in our hospital using fetal magnetic resonance imaging (3 female and 2 male infants). Three of the affected newborns underwent postnatal CT before surgery. In each case, tumor size, its content, mass effect, and classification according to the Altman’s criteria were determined and compared with other features. Fetal magnetic resonance imaging (MRI) and postnatal CT were in excellent agreement with respect to tumor classification using the aformentioned criteria. MRI better characterizes tumor content and its extent compared to ultrasound, and enables a precise structural assessment of the central nervous system. Postnatal CT is complementary to fetal MRI and optional.

Conclusions

Fetal MRI may help in the prenatal diagnosis of SCTs as it overcomes the limitations of obstetric ultrasound. Postnatal computed tomography is useful in determining tumor vascularity or calcifications, and it can depict the surrounding bone structures.

Fetal Body Imaging: When is MRI Indicated?

Recent improvements in fetal therapies and perinatal care and the multidisciplinary involvement in fetal medicine have increased the demand for more accurate prenatal diagnosis. Fetal Magnetic Resonance Imaging (MRI) is a complementary imaging technique for the assessment of thoraco-abdominal anomalies for which Ultrasonography (US) is not conclusive. It is indicated in selected situations to precise the prognosis in diaphragmatic hernia, to characterise the nature and extension of a pulmonary malformation, to locate a bowel atresia or to better depict an abdominal cystic lesion or tumoural extension. It has become a mandatory complementary diagnostic tool and improves the management of the fetuses and newborns.

Parameter set for computer-assisted texture analysis of fetal brain

BACKGROUND

Magnetic resonance data were collected from a diverse population of gravid women to objectively compare the quality of 1.5-tesla (1.5 T) versus 3-T magnetic resonance imaging of the developing human brain. MaZda and B11 computational-visual cognition tools were used to process 2D images. We proposed a wavelet-based parameter and two novel histogram-based parameters for Fisher texture analysis in three-dimensional space.

RESULTS

Wavenhl, focus index, and dispersion index revealed better quality for 3 T. Though both 1.5 and 3 T images were 16-bit DICOM encoded, nearly 16 and 12 usable bits were measured in 3 and 1.5 T images, respectively. The four-bit padding observed in 1.5 T K-space encoding mimics noise by adding illusionistic details, which are not really part of the image. In contrast, zero-bit padding in 3 T provides space for storing more details and increases the likelihood of noise but as well as edges, which in turn are very crucial for differentiation of closely related anatomical structures.

CONCLUSIONS

Both encoding modes are possible with both units, but higher 3 T resolution is the main difference. It contributes to higher perceived and available dynamic range. Apart from surprisingly larger Fisher coefficient, no significant difference was observed when testing was conducted with down-converted 8-bit BMP images.

Magnetic Resonance Imaging Verification of a Case of Sacrococcygeal Teratoma

Although rare, sacrococcygeal teratoma is the most common congenital neoplasm, occurring in 1 in 40,000 infants. Approximately 75% of affected infants are female. The aim of the present study was to correlate ultrasonography and magnetic resonance imaging (MRI) findings in patients with fetal sacrococcygeal teratoma. Three pregnant women in 27th week of gestation underwent fetal MRI after ultrasonography examination, with findings suggestive for fetal sacrococcygeal teratoma. Tumor size, location, extent and content were evaluated both by MRI and ultrasonography. Findings regarding tumor location, size and content were similar for both methods. There was a large well-circumscribed mixed, cystic/solid oval mass, originating from right sacro-gluteal region and projecting into the amniotic cavity, 132 × 110 × 76 mm in size. The mass had a heterogeneous appearance. The T1 high signal suggested fat component of the tumor, while T1 and T2 hypointense components suggested calcified/bony components. There was also T1 hypointense component consistent with cystic and fluid component. The imaging findings were characteristic for sacrococcygeal teratoma. There was not obvious lumbar or thoracic spinal involvement. There was no gross intrapelvic or abdominal extension, and even sacrum and coccyx appeared deformed. The amount of amniotic fluid was increased. MRI was superior to ultrasonography in the evaluation of the exact tumor extent, accurately demonstrating pelvic involvement in all of the three cases. Fetal MRI has shown to be a valuable adjunct to obstetric sonography in the evaluation of fetal sacrococcygeal teratoma, because of its higher accuracy in the determination of tumors extent and content, playing a significant role in the therapeutic planning and increasing the chances of cure for these fetuses.

The clinical relevance of fetal MRI in the diagnosis of Type IV cystic sacrococcygeal teratoma--a review

The introduction of fetal magnetic resonance imaging (MRI) has improved the prenatal evaluation of uterine, placental and fetal anatomy. However, its utilization has mostly been restricted to fetal central nervous system anomalies. We review how adjunct fetal MRI was performed and diagnosis of cystic type IV sacrococcygeal teratoma was made. We also discuss the clinical relevance of fetal MRI in differentiating this lesion from other selected abdominal/pelvic cystic malformations and lesions.

Magnetic resonance imaging of pediatric pelvic masses

Both benign and malignant pelvic masses are encountered in the pediatric population. Although ultrasonography remains the modality of choice for initial evaluation of a pediatric pelvic mass, in selected cases magnetic resonance (MR) imaging can add important diagnostic information. MR imaging has several advantages over ultrasonography and computed tomography, including superior contrast resolution and an ability to characterize abnormalities based on unique tissue characteristics. MR evaluation assists in lesion characterization, presurgical planning, and staging when a malignancy is suspected. MR imaging also offers a nonionizing imaging modality for long-term follow-up of patients undergoing therapy for malignant pelvic masses.

Sacrococcygeal teratoma growth rate predicts adverse outcomes

PURPOSE

The purpose of this study was to characterize the growth rate of sacrococcygeal teratomas (SCTs) and determine its relationship to adverse outcomes.

METHODS

A retrospective review of all pathology-confirmed isolated SCT patients evaluated with at least two documented ultrasounds and followed through hospital discharge between 2005 and 2012 was conducted. SCT growth rate was calculated as the difference between tumor volumes on a late- and early-gestation ultrasound divided by the difference in time. Outcomes were death, high-output cardiac failure (HOCF), hydrops, and preterm delivery. Student's t-test, receiver operator characteristics, Fisher's Exact test, and Pearson's correlation were performed.

RESULTS

Of the 28 study subjects, there were 3 in utero demises and 2 neonatal deaths. Significantly faster SCT growth rates were seen in all adverse outcomes, including death (p<0.0001), HOCF (p=0.005), and preterm delivery (p=0.009). There was a significant association with adverse outcomes at >61cm(3)/week (AUC=0.87, p=0.001, LR=4.52). Furthermore, there was an even greater association with death at >165cm(3)/week (AUC=0.93, p=0.003, LR=18.42). Growth rate was directly correlated with the percent of solid tumor (r=0.60, p=0.0008).

CONCLUSION

Faster SCT growth is associated with adverse outcomes. SCT growth rate determined by ultrasound is an effective prognostic indicator for adverse outcomes and easily applied to patient management.

Giant sacrococcygeal teratoma embolization

Resection of giant sacrococcygeal teratoma with high-vasculature in newborns can be a fatal procedure due to massive bleeding of the tumor. Endovascular embolization of the arteries that supply the tumor may lead to minimal blood loss. We present a case of giant high-vascular sacrococcygeal teratoma type-1 that was embolized in an infant born at 35 weeks gestation. This procedure lead to a safe, surgical resection with minimal bleeding: 12 ml.

Timing of MRI in pregnancy, repeat exams, access, and physician qualifications

This review addresses specific questions regarding performance and utility of fetal MR. The specific issues addressed are (1) physician qualifications; (2) MR safety; (3) access to fetal MR; (4) timing of MRI in pregnancy; (5) repeat exams; and (6) when MRI is most effective for prenatal diagnosis. Fetal MRI is a problem-solving tool used for specific indications that are driven by ultrasound or at times by family history. Fetal MR should always be performed with knowledge of the sonographic findings from prior targeted scan. The best evidence for utility of MR is in assessment of CNS anomalies and assessment of the fetus with airway obstruction requiring decisions regarding mode of therapy. The type of information provided by MR can profoundly impact patient counseling and management. We recommend a team approach including specialists in obstetric imaging, fetal MRI, and postnatal care in interpreting MR so that the best information can be given to the pregnant patient.

Magnetic resonance imaging of the fetal central nervous system, head, neck, and chest

Magnetic resonance imaging (MRI) has become an important tool in the assessment of fetal anomalies. Although ultrasound remains the modality of choice for screening, MRI offers several advantages that permit optimal characterization of anomalies in certain situations. Accurate recognition and characterization of fetal anomalies guides decisions about pregnancy management and coordination of postnatal care. This article will briefly review safety and practical aspects of fetal MRI. We will then provide a concise summary of the most common indications for fetal MRI, and discuss the differential diagnosis and role of MRI in assessment of fetal brain, head, neck, spine, and chest anomalies.

Osteosarcoma cells differentiate into phenotypes from all three dermal layers

BACKGROUND

Osteosarcomas are the most common solid malignant bone tumors, but little is known of their origin. The embryonal rest hypothesis views cancer cells as arising from committed progenitor stem cells in each tissue. Adult tissue contains primitive stem cells that retain the ability to differentiate across dermal lines, raising the possibility that the stem cell of origin of cancers may be from a more primitive stem cell than a progenitor.

QUESTIONS/PURPOSES

Can osteosarcoma cells, when cultured under conditions used for multipotent stem cells, be induced to differentiate into multiple phenotypes, including those of the three different dermal lineages: mesodermal, ectodermal, and endodermal?

METHODS

One rat and one human osteosarcoma cell line were cultured and treated with concentrations of 0, 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) mol/L dexamethasone for 5 weeks. Seventeen phenotypes were assayed either by tissue-specific histochemical stains or antibodies to tissue-specific proteins. Each phenotype was tested across all dexamethasone concentrations for each cell line and each phenotype was tested in three separate experiments with induction by dexamethasone

RESULTS

Rat osteosarcoma (ROS) 17/2.8 and human osteosarcoma cell line U-2 show the appearance of cells that have markers for (1) mesodermal phenotypes such as bone, cartilage, skeletal muscle, and endothelial cells, (2) ectodermal phenotypes such as astrocytes, oligodendrocytes, neurons, and keratinocytes, and (3) an endodermal phenotype, hepatocytes. This indicates osteosarcomas are composed, at least in part, of primitive stem cells capable of differentiating into tissues from all three dermal lineages.

CLINICAL RELEVANCE

If osteosarcomas arise from primitive stem cells, then treatment of osteosarcomas with exogenous differentiation agents may cause the stem cells to differentiate, thus halting their proliferation and stopping tumor growth.

Imaging of unusual perineal masses

OBJECTIVE

The purpose of this article is to describe the radiologic features of unusual tumors that occur in the perineum.

CONCLUSION

The perineal space is often overlooked because of the infrequency of abnormalities. Accurate image interpretation and visualization of extent of pathology is important for proper management. Trauma and infectious diseases occur in the acute setting, whereas tumors are common in the chronic setting. Cross-sectional imaging plays a crucial role in depicting perineal anatomy and evaluating the extent of disease.

Congenital tumors: imaging when life just begins

BACKGROUND: The technical developments of imaging methods over the last 2 decades are changing our knowledge of perinatal oncology. Fetal ultrasound is usually the first imaging method used and thus constitutes the reference prenatal study, but MRI seems to be an excellent complementary method for evaluating the fetus. The widespread use of both techniques has increased the diagnosis rates of congenital tumors. During pregnancy and after birth, an accurate knowledge of the possibilities and limits of the different imaging techniques available would improve the information obtainable, thus helping the medical team to make the most appropriate decisions about therapy and to inform the family about the prognosis. CONCLUSION: In this review article, we describe the main congenital neoplasms, their prognosis and their imaging characteristics with the different pre- and postnatal imaging methods available.

Tumor volume to fetal weight ratio as an early prognostic classification for fetal sacrococcygeal teratoma

PURPOSE

This study was designed to develop a prognostic factor for fetuses with sacrococcygeal teratoma (SCT) that may be useful to predict outcome and guide counseling early in pregnancy. We hypothesize that, in fetuses with SCT, the ratio of tumor size to estimated fetal weight in the second trimester predicts outcome.

METHODS

We retrospectively reviewed charts of all patients evaluated at our Fetal Center for SCT between 2004 and 2009. Estimated fetal weight and tumor volume were calculated based on prenatal ultrasound or fetal magnetic resonance imaging. Patients were stratified based on tumor volume to fetal weight ratio (TFR), and their outcomes were analyzed by Fisher's Exact test.

RESULTS

Tumor volume to fetal weight ratio before 24 weeks' gestation was predictive of outcome. Those with a TFR less than or equal to 0.12 (n = 5) had a significantly better outcome than patients with a TFR greater than 0.12 (n = 5, P < .05). All patients with poor outcomes had a TFR greater than 0.12 by 24 weeks' gestation. A TFR greater than 0.12 predicted poor outcome with 100% sensitivity and 83% specificity. All 4 patients who developed hydrops had a TFR greater than 0.12.

CONCLUSION

In our series of fetuses with SCT, TFR before 24 weeks' gestation correlates with outcome. This novel, prenatal diagnostic tool may be useful in prenatal counseling and for early identification of high-risk fetuses.

The fetal magnetic resonance imaging experience in a large community medical center

Fetal magnetic resonance imaging (MRI) continues to prove a useful problem solving tool for diagnostic and management decision making issues encountered in the antenatal period. In this paper, we attempt to review basic fetal MRI protocol considerations and demonstrate key imaging findings through multiple modalities, with pathologic correlation in several cases. A study of five fetal MRI cases, from our institution, were selected in order to highlight both the indications for, and benefits obtained from this advanced imaging technique. Fetal MRI proved useful in each case in better defining fetal anomalies, especially where ultrasound (due to drawbacks such as shadowing by pelvic bones) was unable to be completely diagnostic. The more in-depth study made possible by MRI also helped with formulation of disease prognosis and estimation of survival chances of the fetus. Further, MRI as a diagnostic and prognostic tool has become more ubiquitous across the medical community. This imparts tangible benefit to patients, who are now able to find this service within arm's reach. Whereas previously these patients were obligatorily referred up to 90 miles away from our centre for further medical work-up, now a large percentage can obtain their prenatal imaging and perinatal care locally. In addition, medical education benefits as new types of cases, those with pathology of the antenatal period, are retained for work-up and management in these large community settings. Cases from our institution exemplify these types of pathologies, from fetal chest masses to a syndromic presentation of bilateral renal agenesis.

Approaches to the management of antenatally diagnosed congenital tumours

Congenital fetal tumours are rare, but current imaging modalities including US and MRI facilitate antenatal diagnosis and investigation, allowing a presumptive diagnosis and management strategy. Although the prevalence of fetal tumours is difficult to ascertain, an incidence of 7.2 per 100,000 live births has previously been reported, with the incidence of neonatal malignancy estimated at 36.5 per million births. Teratomas and neuroblastomas are the most common solid tumours described. Tumours may be very large or associated with severe hydrops leading to significant dystocia with the potential for difficult vaginal or caesarean delivery. Once the diagnosis of a fetal tumour is made, optimal management incorporates a multidisciplinary approach including obstetrician, neonatologist, paediatric surgeon and paediatric oncologist so that counselling is appropriate and a clear management plan is in place for parents.

Tumours of the fetal body: a review

Tumours of the fetal body are rare, but lesions have been reported in all spaces, especially in the mediastinum, the pericardial space, the adrenals, the kidney, and the liver. Lymphangioma and teratoma are the commonest histological types encountered, followed by cardiac rhabdomyoma. Adrenal neuroblastoma is the commonest malignant tumour. Imaging plays an essential role in the detection and work-up of these tumours. In addition to assisting clinicians it also helps in counselling parents. Most tumours are detected by antenatal US, but fetal MRI is increasingly used as it brings significant additional information in terms of tumour extent, composition and complications.

Avaliação crítica dos benefícios e limitações da ressonância magnética como método complementar no diagnóstico das malformações fetais

OBJETIVO: Avaliar, por meio da ressonância magnética, uma série de fetos com diagnóstico ultra-sonográfico de malformação, a fim de estabelecer os benefícios e limites diagnósticos proporcionados pela técnica de ressonância magnética fetal, em comparação com a ultra-sonografia. MATERIAIS E MÉTODOS: Foram estudadas 40 mulheres entre 15-35 semanas de gestação com diagnóstico de anomalia fetal durante o exame de ultra-sonografia. As pacientes foram encaminhadas para o estudo complementar com ressonância magnética. As indicações para o estudo da ressonância magnética fetal foram: anomalias do sistema nervoso central, do tórax, do abdome, renais, esqueléticas e tumores. A avaliação pós-natal incluiu a revisão das imagens de ultra-sonografia e ressonância magnética, o acompanhamento do nascimento, exames laboratoriais, radiológicos e necropsia. RESULTADOS: Os resultados mostraram que os estudos complementares com ressonância magnética fetal trouxeram informações adicionais em 60% dos casos estudados. Os benefícios da ressonância magnética fetal foram: ampliação da avaliação global, aumento do campo de avaliação, maior resolução tecidual pelo uso de seqüências, e avaliação em pacientes obesas e com oligoidrâmnio. Os limites da ressonância magnética fetal foram: evitar exame no primeiro trimestre, avaliação do fluxo sanguíneo, movimentação fetal, claustrofobia materna, estudo do coração fetal e esqueleto. CONCLUSÃO: A ressonância magnética fetal pode ser utilizada como método complementar para a avaliação das malformações fetais.

H, Daltro PA, Rodrigues L, Amim B, Guerra F, Domingues RC, Gasparetto EL. Correlação entre os achados ultra-sonográficos e de ressonância magnética no teratoma sacrococcígeo fetal

OBJETIVO: Correlacionar os achados ultra-sonográficos e de ressonância magnética no teratoma sacrococcígeo fetal. MATERIAIS E MÉTODOS: Três pacientes com idade gestacional entre 30 e 35 semanas, com diagnóstico ultra-sonográfico suspeito de teratoma sacrococcígeo fetal, foram submetidas a ressonância magnética e, posteriormente, a ultra-sonografia para correlação dos achados. Tanto na ressonância magnética quanto na ultra-sonografia foram avaliadas as dimensões, a localização, a extensão e os conteúdos dos tumores. RESULTADOS: A ultra-sonografia e a ressonância magnética obtiveram resultados semelhantes em relação à localização, ao tamanho e ao conteúdo dos tumores. Todas as lesões localizavam-se na região sacrococcígea, com dimensões médias de 6,0 cm x 9,0 cm. Quanto ao conteúdo dos tumores, um dos casos era completamente cístico e dois eram sólidos e císticos. A extensão exata das lesões foi mais bem avaliada pela ressonância magnética do que pela ultra-sonografia, mostrando de forma adequada o acometimento pélvico nos três casos. CONCLUSÃO: A ressonância magnética fetal é capaz de complementar os achados ultra-sonográficos do teratoma sacrococcígeo fetal, uma vez que determina com melhor precisão o conteúdo e a extensão do tumor, auxiliando na conduta terapêutica e aumentando as chances de cura desses fetos.

Fetal oncology

A szerző áttekinti a magzatokban előforduló jó- és rosszindulatú daganatokat. A gyermek- és felnőttkori daganatok szinte minden alakja előfordul méhen belül a magzatokban, illetve világrajövetel után az újszülöttekben. A diagnózis létfontosságú eszköze a szonográfia és a mágneses rezonanciás vizsgálati módszer. Ez a két eljárás nagy előrelépés a kórismézés terén. A kezelések még kísérleti fázisban vannak, és csak néhány központi intézetben végeznek ilyen beavatkozásokat. A választás a műtéti beavatkozás kockázat-haszon arányától függ.

IRM fœtale : indications, limites et dangers

Although prenatal sonography remains the primary imaging method for screening fetal anomalies, fetal MRI with ultrafast imaging technique is a complementary imaging method as soon as the second trimester. It allows better tissue contrast images than does US, a large field of view of the foetus and is not limited by large maternal body habitus and oligohydramnios, without any risk for the foetus. In the future, the development of new techniques (diffusion-weighted imaging, proton MR spectroscopy) and faster sequences will make it possible to widen the indications i.e. cardiac, functional renal and cerebral imaging.

Fetal magnetic resonance imaging

PURPOSE OF REVIEW

Fetal magnetic resonance imaging is becoming more used in the evaluation of complex fetal abnormalities. Rapid advances in the technology and application of fetal magnetic resonance imaging necessitate a review of this subject.

RECENT FINDINGS

Diffusion-weighted imaging, magnetic resonance spectroscopy and functional magnetic resonance imaging may allow assessment of fetal brain even before anatomical abnormalities are demonstrated. We discuss the uses of fetal magnetic resonance imaging in better assessment of pulmonary hypoplasia, congenital diaphragmatic hernia and renal anomalies.

SUMMARY

The additional information from fetal magnetic resonance imaging, beyond that obtained by ultrasound, is invaluable in prenatal counseling, delivery planning and planning for pre- or postnatal intervention. As intrauterine and neonatal surgery evolve, so will the utilization of fetal magnetic resonance imaging.

Diagnosis and characterization of fetal sacrococcygeal teratoma with prenatal MRI

OBJECTIVE

The purpose of this study was to determine whether prenatal MRI provides additional information about fetal sacrococcygeal teratoma compared with prenatal sonography.

MATERIALS AND METHODS

Twenty-two pregnant women with fetal sacrococcygeal teratoma underwent prenatal MRI (mean gestational age, 23 weeks). The size, location, mass characteristics, and compressive effects of the tumors were determined and correlated with sonography and postnatal findings.

RESULTS

Based on the MRI findings, the following American Academy of Pediatrics, Surgical Section classifications were assigned: type I in six patients, type II in 12, and type III in four. No type IV tumors were found. The sacrococcygeal teratoma appeared entirely cystic in five fetuses, microcystic in one, mixed cystic and solid in 12, and solid in four. The diagnosis of sacrococcygeal teratoma was accurate in all cases assessed at our center using both MRI and sonography. Two additional patients initially referred with the diagnosis of sacrococcygeal teratoma had a different diagnosis at reevaluation at our institution (healthy, n = 1; myelomeningocele, n = 1). MRI was superior to sonography for detecting displacement of the colon (n = 11), urinary tract dilatation (n = 9), hip dislocation (n = 4), intraspinal extension (n = 2), and vaginal dilation (n = 1). In fetuses with sacrococcygeal teratoma types II and III, MRI better showed the cephalic extent of the tumor compared with sonography. MRI findings were confirmed at surgery or autopsy in all patients. Three fetuses with high output cardiac physiology underwent open fetal resection of the tumor at 21-, 24-, and 26-weeks' gestational age with two surviving.

CONCLUSION

Our results show that ultrafast fetal MRI is a useful adjunct to the prenatal evaluation of fetal sacrococcygeal teratoma. Compared with sonography, MRI more accurately characterized the intrapelvic and abdominal extent of the tumors and provided more information on compression of adjacent organs. The additional anatomic resolution provided by MRI resulted in more accurate prenatal counseling and improved preoperative planning for surgical resection.

Prenatal diagnosis of anasarca in an end-second trimester fetus presenting with sacrococcygeal teratoma by magnetic resonance imaging

Fetal hydrops is a known complication of sacrococcygeal teratoma (SCT) due to arteriovenous shunts within the tumor, which is clinically important and influence patients' prognosis. We present unique MRI morphological findings of a marked fetal anasarca in a case of an end-second trimester fetus presenting with SCT.

Spontaneous Rupture of Fetal Sacrococcygeal Teratoma

With recent advances in technology, fetal sacrococcygeal teratoma is being diagnosed increasingly during the early prenatal period by ultrasound examination. In addition, early detection of tumor related complications such as polyhydramnios, congestive heart failure, hydrops, hemorrhage, urinary tract or bowel obstruction can be followed closely in utero. Active prenatal management can improve fetal perinatal outcome by allowing planned delivery for neonatal surgery [Chisholm, C.A. et al.: Am J Perinatol 1999;16:47-50] or in some cases, fetal intervention. Additionally, families can be counseled appropriately regarding the range of outcomes. We report a case of fetal sacrococcygeal teratoma Type I diagnosed at 20 weeks with a prominent vessel supplying the tumor mass. At 23 weeks, there was a sudden appearance of an additional lobular mass, consistent with intrauterine spontaneous ruptured of a sacrococcygeal teratoma mass.

Liver, meconium, haemorrhage: the value of T1-weighted images in fetal MRI

BACKGROUND

Ultrafast T2-weighted (T2-W) MRI sequences are currently considered a routine technique for fetal MR imaging. Limited experience exists with fetal T1-weighted (T1-W) imaging techniques.

OBJECTIVE

To determine MRI patterns of some fetal abdominal or haemorrhagic disorders with particular respect to the diagnostic value of T1-W images.

MATERIALS AND METHODS

In addition to standard T2-W single-shot sequences, T1-W single-shot and/or multislice sequences were employed in 25 MR examinations performed in 23 fetuses between 20 and 36 weeks of gestation for more detailed assessment of liver, meconium-filled digestive tract, haemorrhage, or further characterization of a fetal abdominal mass. Diagnostic value and presence of motion artefacts on T1-W images was recorded in each case.

RESULTS

T1-W images enabled superior delineation of fetal liver and large intestine. They provided additional diagnostic information in 9 (39%) of 23 fetuses. One false-positive and one false-negative MRI diagnosis of malrotation anomaly were encountered. Use of single-shot T1-W sequences reduced the occurrence of motion artefacts in 64%.

CONCLUSION

Our results suggest that the specific signal properties of methaemoglobin, meconium and liver are sufficiently important for T1-W sequences to become a routine part of fetal MRI protocols when dealing with digestive tract anomalies, diaphragmatic and abdominal wall defects, intraabdominal masses, and fetal haemorrhage.

Fetal abdomino-perineal lymphangioma: differential diagnosis and management

Fetal lymphangiomas are rare congenital anomalies of the lymphatic system most commonly presenting in the head and neck. Cystic abdominal lymphangiomas are more rare with only a few cases reported prenatally. We report a case of a prenatally detected abdomino-perineal lymphangioma that mimicked the more fatal prenatally detected sacrococcygeal teratoma (SCT), which resulted in one caregiver suggesting termination of the pregnancy. This case demonstrates the importance of carefully considering the differential diagnosis of fetal abdomino-perineal masses when counseling parents.

Obstetric MRI

Ultrasound is the imaging modality of choice for pregnant patients. However, MRI is increasingly utilized in patients in whom the sonographic diagnosis is unclear. These include maternal conditions unique to pregnancy such as ectopic pregnancy, placenta accreta, and uterine dehiscence. MRI is also being increasingly utilized in the assessment of abdominopelvic pain in pregnancy, in particular in assessment for appendicitis. Fetal MRI is performed to assess central nervous system (CNS) abnormalities and patients who are considering fetal surgery for conditions such as neural tube defects, congenital diaphragmatic hernia, and masses that obstruct the airway. In the future, functional MRI and fetal volumetry may provide additional information that can aid in our care of complicated pregnancies.

Giant cystic abdominal masses in children

In this pictorial essay the common and uncommon causes of large cystic and cyst-like abdominal masses in children are reviewed. We discuss and illustrate the following: mesenchymal hamartoma, choledochal cyst, hydrops of the gallbladder, congenital splenic cyst, pancreatic pseudocyst, pancreatic cystadenoma, hydronephrosis, multicystic dysplastic kidney, multilocular cystic nephroma, adrenal hemorrhage, mesenteric and omental cysts, gastrointestinal duplication cyst, meconium pseudocyst, ovarian cysts and cystic neoplasms, hematocolpos, urachal cysts, appendiceal abscess, abdominal and sacrococcygeal teratoma, and CSF pseudocyst. We also describe imaging features and clues to the diagnosis.

Prenatal diagnosis of a cystic type IV sacrococcygeal teratoma mimicking a cloacal anomaly: contribution of MR

OBJECTIVE

To report a case of pelvic midline cystic mass in a female fetus without visibility of the rectum and which is not a cloacal anomaly.

METHODS

Ultrasound (US) and magnetic resonance imaging (MRI) were performed respectively at 27 and 27.5 weeks' gestation and the findings of these examinations were compared with post-mortem examination after termination of pregnancy (TOP).

RESULTS

US showed a pelvic midline cystic mass in a female fetus with mild enlargement of the left ureter and renal pelvis. MRI did not show the T1 hypersignal of meconium in the rectum. The analysis of MR findings were suggestive of the diagnosis of a sacrococcygeal teratoma. Pregnancy was terminated because of the possibility of severe sphincterial disorders and the fetopathological examination confirmed this diagnosis.

CONCLUSION

This observation illustrates the diagnostic problems generated by the detection of a pelvic midline cystic mass in a female fetus. The absence of visibility of the T1 hypersignal of the meconium in the rectum is traditionally supposed to be highly suggestive of a cloaca, but may also be explained by the emptiness of the rectum, compressed by the mass.

From the Archives of the AFIP

Fetal tumors are a diverse group of neoplasms, which are unique in their histologic characteristics, anatomic distribution, and pathophysiology. The biologic behavior of tumors in the fetus may differ dramatically compared with that of the same tumor detected later in life. Teratomas are the dominant histologic type and constitute the majority of both extracranial and intracranial neoplasms. Although often histologically mature, they may prove lethal because of their location and metabolic demands on the fetus. Large solid tumors may lead to cardiovascular compromise and hydrops fetalis. Extracranial teratomas are most commonly located in the sacrococcygeal area, followed by the head and neck, chest, and retroperitoneum. Fetuses with intracranial tumors have a poor prognosis regardless of histologic type. There are, however, two notable exceptions: lipomas and choroid plexus papillomas, both of which have a more favorable outcome. Neuroblastoma is the most common fetal malignancy. It may be either solid or cystic and is more often located on the right side. It typically has favorable biologic markers and stage at presentation. The prognosis for prenatally diagnosed cases is excellent. Other fetal neoplasms include soft-tissue tumors (both benign and malignant), leukemia, mesenchymal hamartoma of the kidney, and liver tumors (hemangioendothelioma, mesenchymal hamartoma, and hepatoblastoma).

Sacrococcygeal Teratoma

Sacrococcygeal teratoma is the most common congenital tumor of the fetus, consisting of all three germ cell layers. These layers are commonly large and vascular, causing the blood to be shunted to the tumor. This creates the vascular steal syndrome, resulting in fetal hydrops and cardiac failure. Large tumors may also cause polyhydramnios, resulting in premature labor. Treatment options include open fetal surgery and radio frequency ablation, as well as complete tumor resection following delivery. Serial sonographic examinations are important in the management of the pregnancy, from diagnosis to treatment and delivery.