The variable sonographic appearances of ovarian teratomas: correlation with CT

Mature Cystic Teratoma: An Integrated Review

Ovarian dermoid cysts, also called mature cystic teratomas (MCTs), account for 69% of ovarian germ cell tumors in young women. The tumors are formed by tissues derived from three germ layers, and sebaceous materials are most commonly seen. The origin of MCTs is widely considered to be the germ cell origin, which completes meiosis I. The clinical symptoms vary widely, but 20% of tumors could be asymptomatic. The diagnosis of MCTs is usually made without difficulty by ultrasound and confirmed by histopathology post-operatively. The imaging findings have a high diagnostic value. The typical characteristics present in the sonographic images, including a dermoid plug or Rokitansky nodule, are considered strong evidence for a teratoma. Although the malignant transformation of MCTs is rare, it can occur in some cases, especially in women of advanced age. The treatment of MCTs depends on the risk of malignancy, the age of the patient, and the patient's fertility reserve requirement. In this article, we review the epidemiology, clinical symptoms, diagnosis criteria, cellular origin, and treatment of mature cystic teratomas.

Ovarian teratomas: clinical features, imaging findings and management

Ovarian teratomas are the most common type of germ cell tumors. There are three major subtypes of ovarian teratomas including mature, immature, and monodermal teratomas. Ultrasound, computed tomography and magnetic resonance imaging can demonstrate specific imaging findings for mature teratoma. Imaging features of immature and monodermal teratomas are less specific, but a combination of clinical features and imaging findings can help in the diagnosis. Imaging is also very helpful in guiding management. In this article, we review the epidemiology, histopathology, clinical presentation, imaging features and management of ovarian teratomas.

Ovarian neoplasms of childhood

Ovarian neoplasms are rare in children. Although usually asymptomatic, they sometimes present with abdominal pain, abdominal distension or palpable mass. The distribution of neoplasms in the pediatric population is different from in adults; benign mature cystic teratoma is the most common ovarian tumor in children. Radiologists should be familiar with the variable sonographic, CT and MRI findings of ovarian neoplasms. Although the less frequently encountered ovarian malignancies cannot be reliably distinguished by imaging alone, it does play an important role in workup. This review discusses the imaging and relevant clinical manifestations of the more commonly encountered pediatric ovarian neoplasms.

Characteristic Fat-Fluid Level at Ultrasonography of Ovarian Dermoid Cyst

An uncommon sonographic pattern was observed in 2 dermoid cysts. An echogenic upper and an echo-free dependent component were separated by a horizontal delineation, an observation that could be reproduced in a laboratory model. We believe that this finding is pathognomonic for a dermoid cyst.

Intra-abdominal fat. Part III. Neoplasms lesions of the adipose tissue

This article focuses on various cancerous lesions that are found beyond organs in the intra-abdominal fat and can be visualized with ultrasonography. These lesions are divided into five groups. The first group includes primary benign tumors containing adipocytes, such as lipoma, lipoblastoma, hibernoma and other lesions with an adipose tissue component, such as myolipoma, angiomyolipoma, myelolipoma and teratoma. The second group comprises primary malignant adipocytecontaining tumors, including liposarcoma and immature teratoma. The third group contains primary benign tumors without an adipocyte component that are located in intra-abdominal fat. This is a numerous group of lesions represented by cystic and solid tumors. The fourth group encompasses primary malignant tumors without an adipocyte component that are located in intra-abdominal fat. These are rare lesions associated mainly with sarcomas: fibrosarcoma, malignant fibrous histiocytoma, hemangiopericytoma and leiomyosarcoma. An epithelioid tumor at this site is mesothelioma. The last but not least group includes secondary malignant tumors without an adipocyte component located in intra-abdominal fat. This is the most numerous group with prevailing carcinoma foci. For each of these groups, the authors present ultrasound features of individual lesions and discuss their differential diagnosis. In the vast majority of cases, the material for cytological and histological analysis can be obtained during ultrasound-guided procedures. This is the advantage of this imaging modality.

A series of malignant ovarian cancers arising from within a mature cystic teratoma: a single institution experience

BACKGROUND

Mature cystic teratoma (MCT) is the most common germ cell tumor. It accounts for 10% to 20% of all ovarian masses. The likelihood of malignancy arising from within an MCT is low, and prognosis is poor.

METHODS

A single-institution retrospective chart review was completed of all cases of MCT from 2004 to 2012. Multiple variables were examined including procedure performed, residual disease after surgery, surgical stage, histologic type, site of primary disease, date of recurrence, whether or not adjuvant chemotherapy was given, and whether or not there was death secondary to disease.

RESULTS

During the study period, 1.2% of MCTs exhibited malignant transformation. The average age at presentation was 53.7 years. Mean follow-up time was 23 months. The most common presenting symptoms were bloating and abdominal pain. The average tumor size was 18 cm. Of note, 33% of cases were at least surgical stage IIIC at the time of presentation, whereas the remainder were stage IC or lower. Four (44.4%) of the 9 cases were identified as mucinous adenocarcinoma in addition to 1 case each of malignant melanoma, squamous cell carcinoma, and poorly differentiated adenocarcinoma. Only 1 patient experienced recurrence. One patient had a known MCT that was being managed expectantly and exhibited malignant transformation to a mucinous adenocarcinoma.

CONCLUSIONS

A large ovarian mass that is suspected to be a mature teratoma should be managed more aggressively in older patients. Our data suggest that although malignancy arising from mature teratomas is rare, it is more likely when patients are older than 40 years, the mass is greater than 18 cm, and there is any suspicion for a mucinous tumor. Like most ovarian tumors, these tumors most often present at later stages and, thus, can be difficult to treat. It is unclear what role chemotherapy or radiation plays in the management of these tumors.

Intra-abdominal fat. Part I. The images of the adipose tissue localized beyond organs

Unaltered fat is a permanent component of the abdominal cavity, even in slim individuals. Visceral adiposity is one of the important factors contributing to diabetes, cardiovascular diseases and certain neoplasms. Moreover, the adipose tissue is an important endocrine and immune organ of complex function both when normal and pathological. Its role in plastic surgery, reconstruction and transplantology is a separate issue. The adipose tissue has recently drawn the attention of research institutes owing to being a rich source of stem cells. This review, however, does not include these issues. The identification of fat is relatively easy using computed tomography and magnetic resonance imaging. It can be more difficult in an ultrasound examination for several reasons. The aim of this paper is to present various problems associated with US imaging of unaltered intra-abdominal fat located beyond organs. Based on the literature and experience, it has been demonstrated that the adipose tissue in the abdominal cavity has variable echogenicity, which primarily depends on the amount of extracellular fluid and the number of connective tissue septa, i.e. elements that potentiate the number of areas that reflect and scatter ultrasonic waves. The normal adipose tissue presents itself on a broad gray scale: from a hyperechoic area, through numerous structures of lower reflection intensity, to nearly anechoic regions mimicking the presence of pathological fluid collections. The features that facilitate proper identification of this tissue are: sharp margins, homogeneous structure, high compressibility under transducer pressure, no signs of infiltration of the surrounding structures and no signs of vascularization when examined with the color and power Doppler. The accumulation of fat tissue in the abdominal cavity can be generalized, regional or focal. The identification of the adipose tissue in the abdominal cavity using ultrasonography is not always easy. When in doubt, the diagnostic process should be extended to include computed tomography or magnetic resonance imaging, or sometimes biopsy (preferably the core-needle one).

Ultrasonography of ovarian masses using a pattern recognition approach

As a primary imaging modality, ultrasonography (US) can provide diagnostic information for evaluating ovarian masses. Using a pattern recognition approach through gray-scale transvaginal US, ovarian masses can be diagnosed with high specificity and sensitivity. Doppler US may allow ovarian masses to be diagnosed as benign or malignant with even greater confidence. In order to differentiate benign and malignant ovarian masses, it is necessary to categorize ovarian masses into unilocular cyst, unilocular solid cyst, multilocular cyst, multilocular solid cyst, and solid tumor, and then to detect typical US features that demonstrate malignancy based on pattern recognition approach.

Ovarian tumors in children and adolescents: a series of 41 cases

OBJECTIVE

Pictorial review with a detailed semiological analysis of ovarian tumors in children and adolescents to provide a relevant diagnostic approach.

PATIENTS AND METHODS

Retrospective study (2001-2011) of 41 patients under the age of 15 who underwent surgery for an ovarian mass with a definite pathological diagnosis.

RESULTS

Sixty-two percent of the lesions were benign, 33% were malignant and 5% were borderline. Germ cell tumors were most frequent (77.5%), followed by sex cord stromal tumors (12.5%) and epithelial tumors (7.5%). Malignant tumors were more frequent in children between 0 and 2 years old. On imaging, calcifications and fat were specific for germ cell tumors; the presence of a mural nodule was predictive of a mature teratoma (P<0.001). Predictive factors for malignancy were clinical, including abdominal distension (P<0.01) or a palpable mass (P=0.05), biological, including increased hCG and/or AFP levels (P<0.001) and radiological, including tumors larger than 12 cm (P<0.05), tumoral hypervascularity (P<0.01) and voluminous ascites (P<0.01).

CONCLUSION

This semiological analysis confirms the role of imaging in diagnosing the etiology of ovarian lesions in children and adolescents and emphasizes the importance identifying tumoral hypervascularity, which, in addition to classic criteria, is highly predictive of malignancy.

Benign teratoma of the thyroid gland

Although pathology reports of thyroid tissue in ovarian teratomas are abundant, benign teratomas of the thyroid are extremely rare in adolescents and adults. Therefore, their clinical characteristics are still not well characterized. We report a case of a 54-year-old woman with a growing mass in her neck. Left lobectomy of the thyroid revealed it to be a benign thyroid teratoma composed of tissues from all three germ layers. Preoperative evaluations included thyroid ultrasonography (US), ultrasound-guided fine needle aspiration cytology (FNAC), and computed tomography (CT) of the neck. A 4.7-cm, well defined, predominantly hypoechoic mass intermingled with hyperechoic internal lesions, was observed in the inferior portion of the left thyroid lobe with substernal extension on US. The posterior extent of the nodule was not visualized due to deep attenuation of the echo. US-guided FNAC failed to reveal any thyroid follicular cells, but suggested a benign cystic tumor. Neck CT hinted at the diagnosis of teratoma because the mass contained large amounts of fat, and the margin was well defined. Extrathyroidal extension and cervical lymphadenopathy were not seen. She underwent left thyroid lobectomy, and histologic examination confirmed benign thyroid teratoma. To the best of our knowledge, this is the first case report of benign thyroid teratoma in Korea.

Imaging of pediatric ovarian neoplasms

We review the clinical and imaging characteristics of the most common ovarian neoplasms in children and adolescents. Because of the widespread use of diagnostic imaging, incidental ovarian neoplasms might be encountered during the evaluation of abdominal pain, trauma or other indications and might pose a diagnostic dilemma. Conducting adequate imaging studies under these conditions is important, as management strategies differ according to the size and appearance of the lesion as well as the age of the patient. US dominates in gynecological imaging because of its excellent visualization, absence of ionizing radiation and sedation risks and comparatively low cost. For further examination of indeterminate lesions found using US, MRI is being used more progressively in this field, particularly for the evaluation of complex pelvic masses with the aim of distinguishing benign and malignant conditions and conditions requiring surgical intervention. CT is reserved primarily for tumor staging and follow-up and for emergency situations.

Imaging of Ovarian Teratomas in Children: A 9-Year Review

Objective

Germ cell tumours are the most common ovarian neoplasms in childhood and, of these, teratomas, whether mature or immature, are the most frequently found. Mature teratoma is a benign tumour, whereas the immature type, although also benign, has a more aggressive course, with a propensity to recurrence. A review of the literature revealed that there are some imaging features that may help to differentiate between these 2 types of teratoma, although no systematic comparison has been made. The objective of this study was to review imaging features of ovarian teratomas in children and to assess differentiating imaging features between the mature and immature types of ovarian teratoma.

Methods

Retrospective analysis of all patients who presented to our institution during a 9-year period (September 1999 to August 2008) with ovarian teratoma as confirmed on histology.

Results

Forty-one patients with pathologically proven ovarian teratoma were found. The patient ages ranged from 4–18 years at presentation (mean [standard deviation] age, 12.4 ± 3.4 years; median age, 13 years). Thirty patients (73.2%) were found to have mature ovarian teratoma, and 11 (26.8%) had immature teratoma. A component of endodermal sinus tumour was found in one of the immature teratomas. On ultrasonography, the appearance of the immature teratomas was purely solid in 3 (27.3%), mixed solid and cystic in 6 (54.5%), and predominantly cystic in 2 (18%). The mature ovarian teratomas demonstrated a predominantly cystic appearance in 22 (73.3%) and a mixed solid and cystic appearance in 8 (26.6%); there were no cases with a pure solid appearance. The prevalence of the more cystic appearance of the mature type showed significant statistical difference when compared with its prevalence in the immature type ( P = .0008, χ2 test). Other imaging features, such as size, presence of fat, or calcifications, did not show a significant difference between the 2 types of teratoma.

Conclusions

The predominance of a cystic component and a pure solid component in ovarian teratoma are significant differentiating factors between the mature type and the more aggressive immature type of teratoma.

Significance of tumour calcification in ovarian carcinoma

The purpose of this study was to assess the pattern and significance of tumour calcification in ovarian carcinoma. Patients with calcifying ovarian carcinoma were identified from radiological reports. Their tumour characteristics, serum calcium levels, treatment and survival were compared with a control group of patients with non-calcifying disease. Patterns and distribution of calcification were assessed. Available serial CT scans were reviewed for changes in both soft-tissue and calcified disease according to RECIST (response evaluation criteria in solid tumours) criteria where feasible. Temporal changes in calcification were correlated with changes in soft tissue disease and CA125 levels. The calcified group numbered 122 (22 other patients had calcifying tumour but insufficient clinical data). Calcification in ovarian carcinoma had a prevalence of 8% (144/1721) in our series. There was a significant difference (p<0.001) between the two groups in the distribution of histological type, with serous tumours being more common in the calcified group (74/122 (61%)) than in the controls (509/1498 (34%)). The calcified tumour patients tended to have lower grade disease (p<0.001). No differences between the groups were found for age, treatment or serum calcium levels. Distribution of calcification was diffusely peritoneal in 34 patients, in association with a pelvic mass in 15, nodal in 11 and within the anterior abdominal wall in 2. There was no correlation between changes in calcification on serial CT scans and corresponding CA125 levels. In conclusion, calcification tends to occur most commonly in serous cystadenocarcinomata and in tumours of lower grade. Changes in calcification cannot be used as a marker of disease response.

Mature and immature ovarian teratomas: CT, US and MR imaging characteristics

Ovarian teratomas (OTs) are the most common germ cell neoplasm. They include mature cystic teratomas, monodermal teratomas (neural tumors, struma ovarii, carcinoid tumors) and immature teratomas. Teratomas are the most common benign ovarian neoplasms in women less than 45 years old. OTs are usually characterized by ultrasound (US) and magnetic resonance (MR) whereas they are usually an incidental finding on CT. The purpose of this paper is to review the most common types of teratomas and to describe CT, US and MR imaging features of the various types of mature and immature OTs.

Histologic, surgical, and imaging correlations of adnexal masses

OBJECTIVE

The purpose of this study was to quantify, categorize, and illustrate discrepancies between preoperative radiologic, surgical, and pathologic diagnoses and to assess the potential impact of discrepancies on clinical care.

METHODS

Adnexal masses reported by pathology during a 16-month period were included if prior imaging at our institution had been performed. Up to 3 sonographic, computed tomographic, and magnetic resonance imaging examinations were reviewed by a gynecologic sonographer and compared with the reported pathologic findings. Cases in which ambiguities were not resolved by consulting the surgical notes were reviewed by a gynecologic pathologist, who confirmed or modified the diagnosis and assigned a score to the pathology quality assurance issue: 0, no pathology quality assurance error; 1, differences in terminology; 2, discrepancy of diagnostic interpretation, benign findings; or 3, discrepancy of diagnostic interpretation, malignant findings.

RESULTS

Of 418 total masses, there was a discrepancy between imaging and pathology in 73 (17%) masses and 68 (21%) pathology reports. Twenty-five (6%) had pathology discrepancies resolved by correlation with the surgical notes alone (eg, torsion seen during surgery but not evident on pathologic examination). Histologic review was performed for 48 (11%) of 418 masses, with pathology errors identified in 34 (71%) of 48. Quality assurance scores were 0 (n = 14), 1 (n = 14), and 2 (n = 20), with no cases receiving a score of 3. Examples of pathology errors included gross (complex versus simple) and microscopic (neoplastic versus functional versus mesothelial) characterization of cysts, sizes of lesions not being described, characterization of fibrous lesions (cystadenofibroma versus cystadenoma), and lack of correlation with imaging (lesions not described).

CONCLUSIONS

This study illustrates the importance of imaging, surgical, and histologic correlation in assessing the diagnostic accuracy of sonography of adnexal masses.

A Practical Approach to the Ultrasound Characterization of Adnexal Masses

Because pelvic ultrasound is commonly used to evaluate adnexal masses, it is important to understand the most useful sonographic features for predicting benign and malignant masses. Determining whether an adnexal mass is of ovarian or extraovarian origin is key in arriving at the most likely diagnosis. Most adnexal masses are benign, and each of the most common benign ovarian lesions has a typical sonographic appearance. Additionally, most malignant ovarian neoplasms have a solid component with detectable flow by Doppler ultrasound, allowing one to strongly suggest the diagnosis. We will review an approach to the ultrasound diagnosis of adnexal masses that progresses through a series of 4 questions to help lead one to the most likely diagnosis.

Numerous intracystic floating balls as a sonographic feature of benign cystic teratoma: report of 5 cases

OBJECTIVE

The purpose of this series was to describe the unusual but unique sonographic pattern of mature cystic teratoma.

METHODS

Five patients of reproductive age with clinical manifestations of a pelvic mass were evaluated with sonography for treatment planning.

RESULTS

All 5 cases showed the similar sonographic pattern of a large cystic tumor filled with multiple echogenic spherical structures floating in the cystic background. Of the 5 patients, 3 had rather large balls varying in size between 1 and 4 cm in the same tumor masses, whereas the other 2 had numerous smaller balls of about 0.5 cm in diameter. The numerous crowded very small echogenic balls in the last 2 cases mimicked solid nodules representing malignancy. However, there was no vascularization in the balls, which suggested a benign nature. The postoperative pathologic diagnosis was mature cystic teratoma without any malignant component in all cases.

CONCLUSIONS

The sonographic feature of intracystic floating echogenic balls is probably pathognomonic for mature teratoma and is easily detected in most cases. Color Doppler sonography is helpful in differentiating these benign nodules (small balls) from malignant tumors.

Magnetic resonance imaging of abdominal pain during pregnancy

The objective of this review is to demonstrate magnetic resonance imaging as an important adjunct to ultrasound and computed tomography in the evaluation of the pregnant patient with abdominal pain. With the advent of ultrafast T2-weighted pulse sequences, fetal and bowel motion cause minimal artifact on the images. An accurate diagnosis can often be made in a few minutes based on these high-contrast images performed in 2 or 3 planes. T1-weighted gradient echo images with and without fat saturation are useful for identifying blood and fat, especially in the case of adnexal masses. Gadolinium-diethylenetriamine pentaacetic acid is rarely used to diagnose inflammatory or obstructive disease and is reserved for those patients with suspected malignancies.

Mature mediastinal teratoma: sonographic imaging patterns and pathologic correlation

OBJECTIVE

To characterize the sonographic patterns of teratomas located within the mediastinum and to correlate them with pathologic findings, because there have been few reports concerning the application of sonography in the diagnosis of mediastinal teratoma.

METHODS

Over a 9-year period, we carried out an image analysis of the sonographic findings of 28 mediastinal teratomas whose diagnoses were proved surgically.

RESULTS

Sonography showed that 18 patients had a complex mass of heterogeneous echogenicity, including regional bright echoes (n = 12), acoustic shadows (n = 8), hyperechoic lines and dots (n = 7), soft tissue septa (n = 9), dermoid plugs (n = 6), and hypoechoic areas (n = 11). This type of mediastinal teratoma revealed, in pathologic findings, varying combinations of fat, sebaceous and mucinous materials, hair, mineralized elements, and multiple compartments. Eight patients had a homogeneous hyperechoic mass, and the 2 remaining patients had floating spherules within a cystic mass. Pathologically, the homogeneous mass mainly contained hair and sebaceous material. The floating spherules were also composed of sebaceous tissue and were above the fluid of the cyst.

CONCLUSIONS

On the basis of the evaluation of the sonographic and pathologic findings, we described 3 major patterns of mediastinal teratoma: a complex mass of heterogeneous echogenicity, homogeneous high echogenicity within a solid mass, and floating spherules within a cystic mass. Thus, sonography can improve the diagnosis of mediastinal teratoma. However, additional prospective studies are needed to test the sensitivity and specificity of these sonographic patterns in the diagnosis of mediastinal teratoma.

Ovarian teratomas: tumor types and imaging characteristics

Ovarian teratomas include mature cystic teratomas (dermoid cysts), immature teratomas, and monodermal teratomas (eg, struma ovarii, carcinoid tumors, neural tumors). Most mature cystic teratomas can be diagnosed at ultrasonography (US) but may have a variety of appearances, characterized by echogenic sebaceous material and calcification. At computed tomography (CT), fat attenuation within a cyst is diagnostic. At magnetic resonance (MR) imaging, the sebaceous component is specifically identified with fat-saturation techniques. The US appearances of immature teratoma are nonspecific, although the tumors are typically heterogeneous, partially solid lesions, usually with scattered calcifications. At CT and MR imaging, immature teratomas characteristically have a large, irregular solid component containing coarse calcifications. Small foci of fat help identify these tumors. The US features of struma ovarii are also nonspecific, but a heterogeneous, predominantly solid mass may be seen. On T1- and T2-weighted images, the cystic spaces demonstrate both high and low signal intensity. Familiarity with the US, CT, and MR imaging features of ovarian teratomas can aid in differentiation and diagnosis.

Unusual "floating balls" appearance of an ovarian cystic teratoma: sonographic and CT findings

Ovarian cystic teratomas are cystic fatty tumors that can be easily diagnosed by sonography and CT. We present a case of ovarian cystic teratoma with an unusual sonographic appearance of mobile, hyperechoic, intracystic fat balls; this finding correlated well with the appearance on CT.

Imaging evaluation of ovarian masses

Adnexal masses present a special diagnostic challenge, in part because benign adnexal masses greatly outnumber malignant ones. Determination of a degree of suspicion for malignancy is critical and is based largely on imaging appearance. Endovaginal ultrasonography (US) is the most practical modality for assessment of ovarian tumors because it is readily available and has a high negative predictive value. Morphologic analysis of adnexal masses is accurate for identifying masses as either low risk or high risk. The most important morphologic features are non-fatty solid (vascularized) tissue, thick septations, and papillary projections. Color Doppler US helps identify solid, vascularized components in a mass. Spectral Doppler waveform characteristics (eg, resistive index, pulsatility index) correlate well with malignancy but generally add little information to morphologic considerations. Computed tomography can help assess the extent of disease in patients before and after primary cytoreductive surgery. Magnetic resonance (MR) imaging is better reserved for problem solving when US findings are nondiagnostic or equivocal because, although it is more accurate for diagnosis, it is also more expensive. The signal intensity characteristics of ovarian masses make possible a systematic approach to diagnosis. Mature cystic teratomas, cysts, endometriomas, leiomyomas, fibromas, and other lesions can be accurately diagnosed on the basis of T1-weighted, T2-weighted, and fat-saturated T1-weighted MR imaging findings.

Transvaginal color Doppler ultrasonic characterization of benign and malignant ovarian cystic teratomas and comparison with serum squamous cell carcinoma antigen

BACKGROUND

The preoperative diagnosis of squamous cell carcinoma (SCC) arising in mature cystic teratoma of the ovary remains difficult. The purpose of this study is to examine the usefulness of transvaginal color Doppler ultrasound (TV-CDU) in differentiating malignant (SCC) from benign cystic teratoma of the ovary.

METHODS

Eighty-eight patients with an ovarian tumor showing gray scale sonographic appearances of mature cystic teratoma were preoperatively evaluated for the presence or absence of intratumoral blood flow by TV-CDU. The blood flow characteristics of the tumor vessels were analyzed using the resistance index (RI), pulsatility index (PI), and peak systolic velocity (PSV). The serum levels of SCC antigen were also randomly examined preoperatively in 50 patients.

RESULTS

Intratumoral blood flow was significantly detected in malignant teratomas (SCCs) (80.0%; 4 of 5) compared with benign teratomas (20.5%; 17 of 83) (P < 0.01). All malignant teratomas with intratumoral blood flow showed both RI less than 0.4 and PI less than 0.6, whereas no benign teratomas showed any such value except for 1 case with struma ovarii. In addition, both the mean RI and the mean PI values in the tumor vessels were significantly lower in the malignant teratomas (RI: 0.31 +/- 0.07; PI: 0.40 +/- 0.16) than in the benign teratomas (RI: 0.62 +/- 0.13; PI: 1.06 +/- 0.44) (P < 0.001). However, the mean PSV value of the malignant teratomas (PSV: 20.6 +/- 8.33) was not significantly different from the benign teratomas (PSV: 18.1 +/- 9.9). Elevation of serum SCC was found in 4 of 5 patients (80%) with malignant teratomas, whereas the elevation was found in 11 of 45 patients (24.4%) with benign teratomas (P < 0.05). The diagnostic accuracy using the RI (cutoff value 0.4) as well as the PI (cutoff value 0.6) was thus 95.2%, which was significantly superior to that obtained by using the serum SCC (76%) (cutoff value, 1.5 ng/mL).

CONCLUSIONS

Evaluating the presence or absence of intratumoral blood flow, together with blood flow resistance, in tumor vessels using TV-CDU thus may be more useful to differentiate malignant (SCC) from benign cystic teratomas of the ovary than by measuring serum SCC levels.

Two Sonographic Presentations of Giant Retroperitoneal Lipomas

Two cases of histologically proven giant retroperitoneal lipomas are presented. Both were evaluated by computed tomography and sonography. Although the computed tomography findings of both lesions were similar, they exhibited different echographic patterns sonographically. In this article, the authors discuss the various ultrasonographic characteristics of body fat, and they present possible explanations.

Adhesion formation from release of dermoid contents in the peritoneal cavity and effect of copious lavage: a prospective, randomized, blinded, controlled study in a rabbit model

OBJECTIVES

To determine, in a rabbit model, whether peritoneal exposure to dermoid cyst material produces inflammation and adhesions above control levels and whether saline lavage reduces the degree of peritoneal reaction.

DESIGN

A prospective, randomized, blinded, controlled study of adhesion formation. Thirty New Zealand white female rabbits were assigned randomly to five experimental groups: [1] laparoscopy with intraperitoneal injection of human dermoid material, [2] laparoscopy with intraperitoneal injection of human dermoid material and subsequent lavage to clear all visible dermoid material, [3] laparoscopy with saline lavage, [4] laparoscopy with intraperitoneal injection of human follicular fluid (antigenic control), and [5] laparoscopy alone.

MAIN OUTCOME MEASURES

Six weeks after initial laparoscopy, inflammation and adhesions were scored in several categories via visual assessment (range 0 to 15) and histologic microscopic evaluation (range 0 to 24). Data were evaluated using Kruskal-Wallis and Mann-Whitney U nonparametric tests.

RESULTS

For groups 1, 2, 3, 4, and 5, respectively, mean +/- SEM total inflammation-adhesion scores were 13.85 +/- 0.55, 2.90 +/- 1.15, 0 +/- 0, 1.50 +/- 1.00, and 0 +/- 0 for clinical evaluation and 16.83 +/- 1.22, 7.33 +/- 1.76, 0 +/- 0,0 +/- 0, and 0 +/- 0 for histologic evaluation. Using nonparametric tests, significant differences were found between groups in clinical and histologic scores.

CONCLUSIONS

Dermoid material produces a significant peritonitis. Results of the clinical evaluation demonstrate that saline lavage brings inflammation and adhesion formation close to control levels. However, results of the histologic evaluation suggest that the decrement in inflammation as a result of lavage may be less dramatic than that found by clinical evaluation.

Imaging of ovarian cancer

Cross sectional imaging continues to play an increasingly important role in ovarian cancer diagnosis, staging, and treatment follow-up. Screening for ovarian cancer remains a controversial subject. The combined use of clinical examination, CA-125, and endovaginal ultrasound (US) are being advocated for high risk patients but consensus recommendation for screening awaits further studies. In characterization of an ovarian neoplasm US is indisputedly the primary imaging approach. Only when US is inconclusive are further studies warranted. Magnetic resonance imaging (MRI) is generally preferred to computer tomography (CT). A prospective MRI-CT clinical trial has not been performed as yet. Preoperative staging by imaging is slowly gaining its acceptance. This is mostly due to the awareness of the difficulties and inaccuracy in surgical staging when unsuspected extensive disease is present. Furthermore, in known resectable ovarian cancer, primary chemotherapeutic cytoreduction may be a better treatment option. Accuracy of CT and MRI in staging ovarian cancer is similar, CT, however, is faster, more widely available, and less expensive; these are important attributes that are decisive in this time of health reimbursement constraints.

Mature cystic teratomas of the ovary: CT and MR findings

OBJECTIVE

To correlate CT and MR patterns of ovarian mature cystic teratomas (MCT).

SUBJECTS AND METHODS

CT and MR findings in 25 histologically proven ovarian MCT were retrospectively reviewed. MCT characterization at CT and MR was based on detection of fat and/or a Rokitansky protuberance. MR signal intensity and CT density numbers of fat were correlated.

RESULTS

At pathology, 24/25 tumors contained fat, 1/25 a water content, and 23/25 a Rokitansky protuberance. Twenty one MCT contained fat with a density number less than-20 HU (mean density: -95 HU) and a signal intensity superior or equal to sub-cutaneous fat on T1 images, however, only six of these had a signal intensity equal to sub-cutaneous fat on T1 and T2 images and 12 had a reversed chemical shift artifact. Three contained fat with a density number ranging from -13 to +8 HU and a signal intensity inferior to subcutaneous fat on T1 images. CT showed a Rokitansky protuberance in 21/23, containing adipose tissue in 16 and calcified structures in 21. Standard MR showed a Rokitansky protuberance in 14/23 and characterized adipose tissue in eight cases, and calcified material in six cases. Finally, CT characterized 24/25 (96%) MCT. Standard MR characterized 22/25 (88%) MCT, and standard MR with fat-suppression sequences characterized 23/25 (92%) MCT.

CONCLUSION

Standard MR is less effective than CT in characterizing fat and has the same difficulty as CT in characterizing fat mixed with hair when its density is high. When fat cannot be identified by either technique, diagnosis of a Rokitansky protuberance is more easily made at CT than at MR.

Preoperative sonography in detecting small benign cystic teratomas

Identification of small ovarian benign cystic teratomas (dermoid cysts) is difficult and sometimes impossible by clinical findings alone. They may be missed even on direct inspection during laparotomy or laparoscopy. There are several typical ovarian sonographic signs which are known to occur frequently in women with benign ovarian cystic teratomas. High-resolution sonography can identify the cysts based on their typical sonographic signs. Since these very small dermoid cysts are sometimes undetected by the naked eye during the operation, ultrasonography with particular attention to the signs is very important. We present three cases reports that illustrate the problem and stress the contribution of preoperative sonography in the diagnosis and treatment of such cases.

Ovarian cystic teratomas: value of chemical fat saturation magnetic resonance imaging

Chemical fat saturation (FS) magnetic resonance imaging (MRI) for the characterization of ovarian cystic teratoma was evaluated in 19 patients with 22 lesions. The tumour was evaluated for signal intensity, location and size; the presence of chemical shift artefact, debris and fat-fluid level. Ovarian cystic teratoma was diagnosed prospectively if the mass contained fat and/or more than one type of internal pattern on (1) SE T1-, T2-, (2) SE T1-, T2-, FS T1-weighted images. A correct diagnosis was reached in 17 of 22 tumours on conventional T1- and T2-weighted images, and in 21 of 22 tumours when fat-saturation images were added. When fat-saturation images were added, four of five tumours misdiagnosed on conventional images were then correctly diagnosed. These tumours contained only small amounts of fat. Fat-saturation images could detect smaller amounts of fat than conventional images. However, one tumour did not show decreased intensity on fat saturation images, and was not diagnosed even when fat-saturation images were added. Fat saturation images have been shown to be of value in diagnosing cystic teratomas.

Primary retroperitoneal teratoma in the adult: correlation of MRI features with CT and pathology

Primary benign teratoma of the retroperitoneum is a rare tumor in the adult population. Only one case with an MRI examination has been reported in the English literature. This paper describes the CT and MRI features of a retroperitoneal teratoma in a 24-year-old male and discusses the value of MRI in the diagnosis and the preoperative imaging of such a tumor.