Cystic teratoma of the ovary: CT detection

CT findings of mature cystic teratoma with malignant transformation: comparison with mature cystic teratoma

PURPOSE

To evaluate the imaging findings of mature cystic teratoma with malignant transformation (malignant teratoma) compared with the corresponding mature cystic teratoma (benign teratoma).

MATERIALS AND METHODS

This study enrolled 1325 patients with 12 malignant teratomas and 1313 benign teratomas. We compared the computed tomographic (CT) findings of eight malignant teratomas and 15 benign teratomas; both groups were matched in terms of tumor size (>9.9 cm) and patient age (>45 years). The CT images were retrospectively evaluated with focus on soft tissue components; size, border (regular or irregular), the presence or absence of nodular formation, enhancement, the angle formed between the soft tissue components and the inner wall of the cyst (acute or obtuse), and transmural growth as well as metastasis including lymphadenopathy and disseminated disease. Using the Fischer's Exact test, each evaluating parameter was compared between the two groups.

RESULTS

Soft tissue components were observed in 75% (six of eight) of malignant teratomas and in 33% (five of fifteen) of benign teratomas; 100% (six of six) of soft component in malignant teratomas had a nodular formation and none of soft component in benign teratomas showed nodular formation; 83% (five of six) of soft component in malignant teratomas had enhancement as well as an obtuse angle between the soft tissue components and the inner wall of the cyst. None of soft component in benign teratomas showed enhancement and 20% (one of five) of soft component in benign teratomas had an obtuse angle; 33% (two of six) of soft component in malignant teratomas showed transmural growth, 13% (one of eight) of malignant teratoma showed lymphadenopathy, and 38% (three of eight) showed disseminated disease. None of benign teratomas showed transmural growth, lymphadenopathy, or disseminated disease. A statistically significant difference between patients with and without malignant transformation was seen in terms of nodular formation, obtuse angle, and enhancement of the soft tissue components (P<.05).

CONCLUSION

Malignant teratoma is characterized by the following imaging findings: the presence of a nodular forming and enhancing soft tissue component, an obtuse angle between the soft tissue and the inner wall of the cyst, as well as extracapsular tumor growth with extension into adjacent structures or metastasis. Therefore, we can differentiate malignant teratoma from benign teratoma using CT findings.

Squamous cell carcinoma arising from mature cystic teratoma of the ovary

OBJECTIVE

Squamous cell carcinoma (SCC) is the most common type of malignant transformation in mature cystic teratoma (MCT) of the ovary. The SCC is difficult to preoperatively diagnose. We conducted a retrospective study to seek the possible risk/prognostic factors and treatments for SCC arising from MCT of the ovary.

METHODS

Using an institutional database, we identified 3 women treated for SCC arising from an MCT of the ovary at the Kaohsiung Veteran General Hospital. A retrospective chart review was conducted, with information obtained from radiographs, operative reports, pathology reports, and radiation oncology records.

RESULTS

A total of 1551 cases of MCT were diagnosed at Kaohsiung Veteran General Hospital from 1990 to 2009, of which, malignant teratoma SCC type was noted in 3 cases (0.19%). The median age of the subjects was 39 years. Abdominal fullness was the most common symptom (3/3 cases). The mean diameter of the ovarian tumor was 17.3 cm, ranging from 16 to 18 cm. All 3 patients received simple right salpingo-oophorectomy or debulking surgery. Two of the patients reached stage IIIC and died.

CONCLUSIONS

: With our review as basis, we recommend being cautious of the following risk factors: patient age, tumor size, ultrasound characteristics, sonar tumor vessel wave form, computed tomography, and levels of SCC and CA125 tumor markers. We suggest that patients have regular ovarian ultrasound examination. Based on our literature review, stage IA patients who undergo standardized operational procedures do well without adjuvant treatment, but such patients must be confirmed accurately with complete surgical staging to be in stage IA before undergoing conservative management. The optimal approach to the management of patients with advanced stage and recurrent disease is unclear. Surgical cytoreduction with proper staging, adjuvant therapy with platinum-based or paclitaxel-based chemotherapy, and concurrent whole pelvic radiation have been recommended as possible methods of treatment.

Screening for tumours in paraneoplastic syndromes: report of an EFNS task force

BACKGROUND

paraneoplastic neurological syndromes (PNS) almost invariably predate detection of the malignancy. Screening for tumours is important in PNS as the tumour directly affects prognosis and treatment and should be performed as soon as possible.

OBJECTIVES

an overview of the screening of tumours related to classical PNS is given. Small cell lung cancer, thymoma, breast cancer, ovarian carcinoma and teratoma and testicular tumours are described in relation to paraneoplastic limbic encephalitis, subacute sensory neuronopathy, subacute autonomic neuropathy, paraneoplastic cerebellar degeneration, paraneoplastic opsoclonus-myoclonus, Lambert-Eaton myasthenic syndrome (LEMS), myasthenia gravis and paraneoplastic peripheral nerve hyperexcitability.

METHODS

many studies with class IV evidence were available; one study reached level III evidence. No evidence-based recommendations grade A-C were possible, but good practice points were agreed by consensus.

RECOMMENDATIONS

the nature of antibody, and to a lesser extent the clinical syndrome, determines the risk and type of an underlying malignancy. For screening of the thoracic region, a CT-thorax is recommended, which if negative is followed by fluorodeoxyglucose-positron emission tomography (FDG-PET). Breast cancer is screened for by mammography, followed by MRI. For the pelvic region, ultrasound (US) is the investigation of first choice followed by CT. Dermatomyositis patients should have CT-thorax/abdomen, US of the pelvic region and mammography in women, US of testes in men under 50 years and colonoscopy in men and women over 50. If primary screening is negative, repeat screening after 3-6 months and screen every 6 months up till 4 years. In LEMS, screening for 2 years is sufficient. In syndromes where only a subgroup of patients have a malignancy, tumour markers have additional value to predict a probable malignancy.

A pictorial review of imaging of abdominal tumours in adolescence

Neoplastic abdominal tumours, particularly those originating from embryonal tissue (such as hepatoblastoma and nephroblastoma) and neural crest cells (such as neuroblastoma), are well-documented in young children. Neoplasms of adulthood, most commonly carcinoma of different visceral organs, are also well-documented. Abdominal tumours in adolescence constitute a distinct pathological group. The radiological features of some of these tumours have been described only in isolated reports. The purpose of this pictorial essay was to review the imaging findings of various kinds of abdominal tumours in adolescent patients (with an age range of 10-16 years) who presented to the Children Cancer Center of our institution in the past 15 years. Some tumours, though rare, have characteristic imaging appearances (especially in CT) that enable an accurate diagnosis before definite histological confirmation.

Imaging of ovarian teratomas: appearances and complications

Ovarian teratomas are the most common germ cell neoplasm. Subtypes of teratoma include mature cystic, immature and the monodermal teratomas. The benign cystic teratoma shows typical imaging manifestations and can be complicated by torsion, rupture and uncommonly malignant degeneration. Uncommon subtypes of teratomas include the immature, which is usually malignant at diagnosis. The growing teratoma syndrome is an uncommon complication reported in patients treated for immature teratomas. The monodermal teratomas which include the struma ovarii may also have specific imaging characteristics that should be recognised on imaging. This paper aims to provide a comprehensive review describing the spectrum of imaging findings of these ovarian tumours and associated complications.

Value of magnetic resonance imaging for the diagnosis of ovarian tumors: a review

This article reviews the value of magnetic resonance imaging (MRI) for the diagnosis of ovarian tumors especially when ultrasonography is indeterminate. Although ultrasonography is the first imaging technique used to investigate suspected pelvic masses, it has a limited capacity for tissue characterization. In addition to morphological characteristics, many tissue parameters such as T1, T2, perfusion, and diffusion contribute to signal intensity, so MRI is able to identify various types of tissue contained in pelvic masses. Magnetic resonance imaging helps to locate large solid masses and to distinguish benign from malignant ovarian tumors, with an overall accuracy of 88% to 93% for the diagnosis of malignancy. The aims of this review are 3-fold. First, we review state-of-the-art and usual MRI techniques and published findings. Second, we recall the MR features most useful for assessing the main ovarian tumors. Finally, we discuss the relevance of various features for distinguishing between benign, borderline, and invasive ovarian tumors.

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.

Imaging findings of complications and unusual manifestations of ovarian teratomas

Ovarian teratomas can be associated with various complications and demonstrate a wide spectrum of clinical and imaging features. The complications include torsion (16% of ovarian teratomas), rupture (1%-4%), malignant transformation (1%-2%), infection (1%), and autoimmune hemolytic anemia (<1%). These complications require different therapeutic strategies; therefore, timely and accurate diagnosis of these complications is important for optimal patient treatment. In cases of complicated ovarian teratomas, the clinical manifestations provide only limited information and often overlap with those of other diseases. Furthermore, ovarian teratomas may have unusual clinical and imaging manifestations, thereby leading to misdiagnosis. These unusual manifestations include immature teratomas, monodermal teratomas (struma ovarii), combination tumors and collision tumors containing teratomas, and mature cystic teratomas without demonstrable fat or with pure fatty components. To provide adequate treatment and prevent misdiagnosis, it is necessary to be familiar with the imaging findings of both the complications and the unusual manifestations of ovarian teratomas.

Meat balls: a pathognomonic ultrasound and computed tomography finding in mature cystic teratoma

One of the commonest germ cell tumours are mature cystic ovarian teratomas. Although the imaging features of teratomas are highly variable, the sonographic and CT identification of fatty and calcific components are fairly suggestive. The case presented, however, is of an unusual, yet pathognomonic CT and ultrasound imaging appearance of an ovarian teratoma that was due to floating balls.

[Degeneration of dermoid cysts: a case study of malignant transformation]

Malignant transformation of ovarian dermoid cyst (mature cystic teratoma) is rare and most often established in postmenopausal women after surgery by sample anatomopathological analysis. We report the case of a 58-year-old woman showing abdominal pain associated with constipation episodes. The diagnosis of dermoid cyst was established upon ultrasonographic and tomodensitometric criteria. Its histopathological analysis confirmed the presence of a well differentiated epidermoid carcinoma. In line with the literature, our study highlights the importance of the age of the patient, the size of dermoid cyst and its growth rate as well as squamous cell carcinoma (SCC) antigen serum level. These date are collected in order to establish a correct diagnosis and provide an appropriate cure. When a cyst is discovered these data must pathological event, mostly observed in menopaused women. Certainty diagnosis is collected in order to establish a correct diagnosis and provide an appropriate cure.

Ovarian Mucinous Tumors Associated With Mature Cystic Teratomas

Most primary ovarian mucinous tumors are of surface epithelial-stromal origin and exhibit diffuse expression of cytokeratin 7 (CK7) combined with variable expression of cytokeratin 20 (CK20); this immunoprofile distinguishes them from most lower gastrointestinal tract tumors secondarily involving the ovaries. The uncommon ovarian mucinous tumors of germ cell (teratomatous) origin have not been extensively evaluated to determine the utility of these markers and other markers of intestinal differentiation for distinguishing these tumors from metastatic gastrointestinal tract mucinous tumors. Immunohistochemical expression of CK7, CK20, CDX2, and villin was assessed in 44 ovarian mucinous tumors associated with a mature cystic teratoma. All cases lacked evidence of a nonovarian primary mucinous tumor. All mucinous tumors were unilateral; 6 cases had bilateral teratomas. All tumors displayed gastrointestinal-type mucinous differentiation, with epithelium that was commonly goblet cell-rich or hypermucinous; 21 were associated with pseudomyxoma ovarii and 3 of these had pseudomyxoma peritonei. Tumor architecture ranged from purely cystadenomatous (n=24), to proliferative (n=13), to carcinomatous (n=6); some tumors had admixtures of these patterns. One tumor had a goblet cell carcinoidlike pattern with pseudomyxoma ovarii. Three carcinomas had a signet ring cell component. Cystadenomatous tumors without pseudomyxoma ovarii (n=15) exhibited all possible CK7/CK20 coordinate expression profiles with nearly equal frequency. All proliferative tumors without pseudomyxoma ovarii (n=8) expressed CK7, most often in combination with CK20 expression. All cystadenomatous and proliferative tumors with pseudomyxoma ovarii (n=9 and n=5) were CK7-/CK20+. All carcinomatous tumors had pseudomyxoma ovarii; 3 were CK7-/CK20+, 2 were CK7+/CK20+, and 1 was CK7+/CK20-. The presence of pseudomyxoma ovarii was significantly associated with a CK7-/CK20+ profile (86% with pseudomyxoma ovarii vs. 13% without, P<0.0001), CDX2 positivity (79% vs. 0%, P<0.0001), and villin positivity (57% vs. 5%, P=0.0009). A subset of mucinous tumors associated with mature cystic teratomas exhibiting morphologic and immunohistochemical features of lower intestinal tract-type mucinous tumors may be teratomatous in origin. In practice, the more common diagnosis of secondary involvement by a lower intestinal tract mucinous tumor should be addressed in the pathology report and in subsequent clinical evaluation; interpretation as a true primary ovarian mucinous tumor of teratomatous origin can be considered as an alternative diagnosis when evaluation and follow-up fail to identify a nonovarian source of the mucinous tumor. Those tumors having CK7 expression with or without CK20 expression may be derived from upper gastrointestinal tract-type or sinonasal-type teratomatous elements but could be independent tumors of surface epithelial-stromal origin.

Large calcifications in ovaries otherwise normal on ultrasound

OBJECTIVE

To evaluate calcifications >or= 5 mm in length in ovaries that are otherwise normal on ultrasound, and to determine whether such large ovarian calcifications are an indicator of ovarian neoplasm.

METHODS

This was a retrospective study reviewing pelvic ultrasound results at our unit between October 1994 and April 2002 to identify patients with ovarian calcifications that were >or= 5 mm in maximum length in otherwise normal ovaries, and who also had follow-up imaging studies. Patient medical histories were reviewed, calcification characteristics, including number, size, shape and laterality of calcifications, were recorded and follow-up imaging studies were reviewed to assess change in size of the calcification and to see if a neoplasm had developed.

RESULTS

The study group consisted of 28 patients. The mean length of imaging follow-up was 35.2 +/- 30.7 months. The mean size of the calcifications was 7.4 +/- 2.3 (range, 5-13) mm. The calcification remained stable in all 28 patients and no ovarian neoplasms developed in any of the patients. Histological confirmation was available in one patient and this revealed dystrophic calcification in a corpus albicans.

CONCLUSION

Calcifications ranging from 5 to 13 mm in length in otherwise normal ovaries remain stable on follow-up imaging and are not an indicator of current or future ovarian neoplasm. Published by John Wiley & Sons, Ltd.

Value of Dynamic Enhanced Magnetic Resonance Imaging for Distinguishing Between Ovarian Fibroma and Subserous Uterine Leiomyoma

PURPOSE

The purpose of this study was to assess the accuracy of magnetic resonance imaging (MRI), particularly, dynamic MRI, in distinguishing ovarian fibromas from subserous uterine leiomyomas.

MATERIAL AND METHODS

Fifteen ovarian fibromas and 15 subserous uterine leiomyomas were retrospectively reviewed. All MR examinations included dynamic contrast-enhanced (DCE) sequences. Morphological criteria (size, T1 and T2 signals, ovarian tissue, associated uterine leiomyoma, and pelvic fluid), arterial vessels, time-intensity curves (maximal enhancement and signal intensity at 30, 60, and 90 seconds), and signal intensity on delayed T1-weighted images were compared between the 2 groups.

RESULTS

No significant difference in morphological criteria was noted between the 2 types of masses. Visualization of arterial vessels was more frequent in uterine leiomyomas than in ovarian fibromas (P= 0.002). The DCE MR enhancement rate was higher for uterine leiomyomas than for ovarian fibromas in terms of both maximal enhancement (P < 0.001) and enhancement rate at 30 (P = 0.009), 60 (P = 0.007), and 90 seconds (P = 0.0009). On delayed T1 postcontrast sequence, no statistical difference exists between signal intensity of ovarian fibromas and uterine leiomyomas.

CONCLUSION

Our findings suggest that DCE MRI can distinguish ovarian fibromas from uterine leiomyomas and should be used if sonography fails to show the origin of a pelvic mass.

Preoperative diagnosis of mature cystic teratoma with malignant transformation: analysis of imaging findings and clinical and laboratory data

PURPOSE

To evaluate the factors including the imaging findings and clinical and laboratory data that were useful for diagnosing mature cystic teratomas with malignant transformation.

MATERIALS AND METHODS

In 11 patients, we analyzed the imaging findings by the CT and MR focused on the soft tissue components for the following characteristics: size; the angle between the soft tissue components and the inner wall of the cyst (acute or obtuse); the configuration of the inner border (regular or irregular); and enhancement as well as tumor size. Clinical and laboratory data such as age, serum SCC, CA-125, CA 19-9, and AFP, were also determined.

RESULTS

In the analysis of the imaging findings, nine (82%) of all tumors had soft tissue components and eight (89%) of nine soft-tissue-containing tumors showed an obtuse angle between the soft tissue components and the inner wall of the cyst as well as enhancement. In nine (82%) of the study patients it was shown that the largest diameter of the tumor was larger than 9.9 cm and the patients were older than 45 years. In the results of the laboratory data, six (67%) of performed nine patients had a CA-125 elevation greater than 35 U/ml and three (75%) of performed four patients had a CA 19-9 elevation greater than 37 U/ml.

CONCLUSION

We suggest that preoperative diagnosis may be improved and available in cases of synthesized imaging findings with clinical and laboratory data.

Intestinal adenocarcinoma arising in a mature cystic teratoma of the ovary: A case report

Gastrointestinal adenocarcinoma arising in mature cystic teratomas of the ovary is extremely rare. We report a case of well-differentiated intestinal adenocarcinoma arising in a mature cystic teratoma of the ovary in a 77-year-old woman, presenting as acute abdomen with ovarian torsion. An immunohistochemical study revealed expression of CK20 and CK7, and the tumor was also positive for MUC2. The patient had no evidence of disease after 12 months of follow-up.

A case of mesenteric cystic lymphangioma: fat saturation and chemical shift MR imaging

Mesenteric cystic lymphangioma is an uncommon lesion that may be difficult to diagnose radiologically. In our case, a septate cystic mass showed fluid attenuation on a computed tomography scan. We were able to define the fat content within the cystic tumor by magnetic resonance (MR) imaging. The presence of fat within an intra-abdominal cystic mass is suggestive of a dermoid cyst, cystic lymphangioma, or lymphocele. The pathologic diagnosis revealed a cystic lymphangioma, which originated from the mesentery. Although the MR imaging features of dermoid cysts and lymphangiomas are well known, the demonstration of fat content by chemical shift and fat saturation MRI has not yet been reported for a cystic lymphangioma.

MR imaging compared with intraoperative frozen-section examination for the diagnosis of adnexal tumors; correlation with final histology

The aim was to compare the accuracy of magnetic resonance imaging (MRI) and intraoperative consultation (IC) for the diagnosis of adnexal masses, with reference to final histology. MRI was performed in 136 women with sonographically indeterminate adnexal masses. IC included macroscopic and frozen-section examination. Macroscopic examination and MRI determined size, nature, and presence of vegetations or solid portions within masses. All masses were characterized as benign or malignant according to previously published MR imaging and histopathologic criteria. Sensitivities, specificities, and predictive values for the diagnosis of malignancy of MRI and IC were assessed. Histology revealed 168 adnexal masses (99 benign, 23 borderline and 46 invasive). Frozen sections were examined in 151 cases. Among the 151 adnexal masses studied by both MRI and IC, respective sensitivities, specificities, positive and predictive values of both methods for the diagnosis of malignancy were 89.7% and 84.5%, 91.4% and 100%, 86.7% and 100%, and 93.4% and 91.3%. Sensitivities of MR imaging and frozen section for the diagnosis of serous versus mucinous borderline tumors were 33.3% and 93.3%, and 62.5% and 12.5%, respectively. MRI is less accurate than IC for characterizing adnexal masses. However, MRI may increase the relevance of IC for borderline mucinous tumors.

Malignant transformation within a dermoid cyst: a case report and literature review

Malignant transformation within a dermoid cyst is a rare event. The most common transformation is to squamous cell carcinoma. Patients are often elderly and present with advanced disease. The prognosis tends to be very poor. We present a case of locally invasive squamous cell carcinoma arising from a dermoid cyst in a 48-year-old lady. She underwent debulking surgery with no gross residual disease remaining. Within 2 months of the surgery she had recurrent disease and this was resistant to single agent carboplatin chemotherapy. She died 4 months after her initial surgery. We discuss the difficulties in diagnosing such tumours, the poor prognosis and review the various adjuvant treatment strategies that have been used in attempt to improve the outcome.

CT and MR imaging of extrahepatic fatty masses of the abdomen and pelvis: techniques, diagnosis, differential diagnosis, and pitfalls

The differential diagnosis of extrahepatic abdominopelvic masses is wide. Demonstration of fat within a lesion at noninvasive imaging is an important clue for narrowing the differential diagnosis. Macroscopic fat is readily identified with both computed tomography (CT) and magnetic resonance (MR) imaging. Demonstration of microscopic fat is more difficult and may require special techniques. Identification of fat with CT is based on x-ray resorption and therefore on the attenuation (typically less than -20 HU). Several MR imaging techniques have been developed for fat suppression. Two of the most widely available are spectroscopic fat saturation and chemical shift (in-phase/opposed-phase) imaging. Entities with predominantly macroscopic fat include myelolipoma, angiomyolipoma, teratoma, liposarcoma, lipoma, epiploic appendagitis, omental infarction, and mesenteric panniculitis. Lesions with predominantly microscopic fat include adrenal adenoma and some teratomas. Other fat-containing entities involve the mesentery and bowel wall; these include fibrofatty mesenteric proliferation and submucosal fat deposition.

Helical CT Evaluation of Acute Right Lower Quadrant Pain: Part II, Uncommon Mimics of Appendicitis

OBJECTIVE

The purpose of our pictorial essay is to highlight the helical CT features of uncommon mimics of appendicitis and to provide clues to differentiate them from appendicitis.

CONCLUSION

Uncommon mimics of appendicitis create a diagnostic challenge in patients with right lower quadrant pain. Recognition of the helical CT features of uncommon mimics of appendicitis is important in clinical management and avoiding unnecessary laparotomy.

Malignant transformation of an ovarian mature cystic teratoma: computed tomography findings

INTRODUCTION

The malignant transformation of an ovarian mature cystic teratoma is rare. We presented such a case of a 46-year-old woman with characteristic computed tomography (CT) findings.

CASE REPORT

The patient had suffered from fullness and tenderness of the lower abdomen for one year. A high serum CA-125 level was noted. Computed tomography images showed a left adnexal mass with fat, calcification and soft tissue components, and areas of invasion through the teratoma wall.

OUTCOME

The histologic diagnosis was compatible with a squamous cell carcinoma arising from a mature cystic teratoma of the ovary.

Ovarian teratoma diagnosis and management: case presentations

BACKGROUND

Ovarian teratomas (OTs) may be of mature or immature morphologies. Mature cystic teratomas (MCTs), often referred to as dermoid cysts, are the most common germ cell tumours of the ovary in women of reproductive age. OTs are usually asymptomatic until they reach considerable size. Frequently, ultrasonography is diagnostic. Women requiring surgery for OTs should be appropriately counselled about the risks and benefits of laparoscopic and open approaches.

CASE PRESENTATIONS

Case I: An 18-year-old woman presented with hirsutism and irregular menses, both of which reversed after bilateral MCT removal by laparoscopy. Case II: A 47-year-old multigravid woman presented with a large unilateral OT, with a focus of malignancy. Case III: A 19-year-old woman presented with a large unilateral OT associated with gliomatosis peritonei.

CONCLUSION

Experienced laparoscopic surgeons should consider laparoscopy as an alternative to laparotomy in management of OT in selected cases. Women younger than 15 years of age or older than 45 years of age who have large, solid teratomas on ultrasound or positive markers for germ cell tumours are at risk for malignant variants, and for these women laparotomy is the preferred approach.

Computed Tomography and Magnetic Resonance Imaging Findings in Cases of Dermoid Cyst Coexisting with Surface Epithelial Tumors in the Same Ovary

OBJECTIVE

The purpose of this work was to describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings in cases of dermoid cysts coexisting with surface epithelial tumors in the same ovary.

METHODS

The pathologic reports of 141 dermoid cysts, 97 mucinous and 35 serous tumors were reviewed. The CT and/or MR images in the cases with a dermoid cyst and a surface epithelial tumor coexisting in the same ovary were analyzed.

RESULTS

Eleven cases of mucinous tumors (6 benign, 3 low-grade, and 2 malignant) coexisted with dermoid cysts. Mucinous tumors were found in coexistence with 11.3% of dermoid cysts, and dermoid cysts were found in coexistence with 7.8% of mucinous tumors. In 10 cases, 3 radiologic patterns were observed: small fatty foci in the septa of the cystic tumor, an adjacent fat-containing component and a septated cystic component, and a dermoid cyst with no detectable mucinous tumor component. No histopathologically specific differences were observed between these groups. Small amounts of mucinous components were difficult to detect, but small fatty foci were easily detected. In 1 case, mucinous carcinoma formed a mass lesion in the wall of the dermoid cyst.

CONCLUSIONS

The coexistence of these two neoplasms was not rare. If a dermoid cyst accompanies a multiseptated cyst and if the multiseptal cyst contains fatty foci, these two components may be associated. Recognizing the potential for the coexistence of these two neoplasms in the same ovary is essential for making a correct diagnosis.

Presacral dermoid cyst with scanty fat component: usefulness of chemical shift and diffusion-weighted MR imaging

We present a case of a dermoid cyst located at the presacral space. Although CT and conventional MR (T1- and T2-weighted images) demonstrated a non-specific cystic mass with little evidence of calcification or fat, chemical shift and diffusion-weighted MR imaging suggested the presence of small amount of fat and abundant keratinoid substance within the tumor, respectively. Pre-operative diagnosis of dermoid cyst was made. The tumor was surgically resected and the diagnosis was confirmed. Chemical shift and diffusion-weighted MR imaging are useful in the diagnosis of dermoid cyst with little evidence of calcification and fat.

MRI Findings of an Ovarian Dermoid Cyst with Malignant Transformation

The ovarian dermoid cyst is the most common ovarian tumor. However, malignant transformation developing from a dermoid cyst is very rare. Because of this rarity, few reports exist of preoperative diagnosis of this tumor by MRI. We report MRI findings from a 69-year-old patient with a malignant transformation (squamous cell carcinoma with sarcomatoid features) in a right ovarian dermoid cyst.

CT and MR imaging of ovarian tumors with emphasis on differential diagnosis

Ovarian tumors are classified on the basis of tumor origin as epithelial tumors (serous and mucinous tumors, endometrioid and clear cell carcinomas, Brenner tumor), germ cell tumors (mature and immature teratomas, dysgerminoma, endodermal sinus tumor, embryonal carcinoma), sex cord-stromal tumors (fibrothecoma; granulosa cell, sclerosing stromal, and Sertoli-Leydig cell tumors), and metastatic tumors. Epithelial tumors are primarily cystic and, when malignant, are associated with varying proportions of a solid component. Papillary projections are a distinctive feature of epithelial tumors. Profuse papillary projections are highly suggestive of borderline (low-malignant-potential) or malignant tumor. Ovarian teratomas demonstrate lipid material at computed tomography and magnetic resonance (MR) imaging. Malignant germ cell tumors manifest as a large, complex abdominal mass that contains both solid and cystic components. Tumor markers are helpful in diagnosis. The radiologic appearance of sex cord-stromal tumors varies from small solid masses to large multicystic masses. Granulosa cell tumors are usually large multicystic masses with solid components. Fibrothecoma, sclerosing stromal tumor, and Sertoli-Leydig cell tumors are usually solid masses. Fibromas have very low signal intensity on T2-weighted MR images. Certain radiologic findings predominate for each type of tumor. Knowledge of these key features of ovarian tumors provides the criteria for making a specific diagnosis or substantially narrowing the differential diagnosis.

Staging ovarian cancer: role of imaging

Ovarian cancer is relatively common, and often presents at an advanced stage with widespread intraperitoneal metastases. The constellation of complex pelvic masses, ascites, omental cake, and other peritoneal implants is virtually diagnostic. All patients are potential surgical candidates, since suspected early stage disease is treated by a comprehensive staging laparotomy including total abdominal hysterectomy, bilateral salpingo-oophorectomy, and omentectomy. Operable advanced disease is treated by surgical debulking and adjuvant combination chemotherapy. The role of imaging is to detect and characterize adnexal masses as likely malignant, recognize unusual findings that may suggest atypical pathology, demonstrate metastases in order to prevent under-staging, and detect specific sites of disease that may be unresectable. These aims are directly related to clinical management; characterization of an adnexal mass as malignant guides appropriate surgical referral, recognition of atypical pathology such as malignant granulosa cell tumor in a young woman may be an indication for fertility-preserving surgery. Demonstration of metastatic site-assists surgical planning, and detection of unresectable disease may be an indication for neoadjuvant (ie, preoperative) chemotherapy with interval debulking rather than primary debulking with adjuvan (postoperative) chemotherapy.

Laparoscopic surgery of dermoid cysts--intraoperative spillage and complications

OBJECTIVE

To assess the risks of complications including intraoperative spillage following laparoscopic dermoid cyst enucleation.

STUDY DESIGN

A retrospective case series comparison of 390 patients who had surgery at our hospital from 1992 to 1998 for teratomas of the ovary.

RESULTS

43 patients were treated with laparotomy. Two malignant teratomas were observed in this group. In seven patients, the dermoid cysts were removed as part of a vaginal hysterectomy. Three hundred and forty patients had surgery via laparoscopy. Enucleation of the dermoid cyst in toto using a salvage bag for removal was only possible in few cases without contamination of the abdominal cavity by spillage of cyst contents. There were no serious complications in any patients including those with laparoscopic cystectomies and intraperitoneal spill.

CONCLUSION

The laparoscopic treatment of benign teratomas is a safe procedure. Primary laparotomy as well as adenectomy is also to be taken into consideration with young patients, if suspicion of malignancy, rapid growth, doubtful infiltration or large size of tumor is present.

Sonographic and MRI findings in prepubertal adnexal hemorrhagic cyst with torsion

Adnexal torsion is rare before menarche. We report the case of a 10-year-old girl with persistent left lower quadrant pain proven by surgery to be caused by adnexal torsion due to a hemorrhagic cyst. Sonography showed a well-defined, complex, predominantly solid mass with some sound through-transmission and a small amount of fluid. The left ovary could not be distinguished from the mass; the right ovary appeared normal. Doppler sonography demonstrated no blood flow within the mass. MRI revealed a circumferential region of high signal intensity in the periphery of the mass and multiple hyperintense foci in the left ovary.

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.

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.

Value of fat-suppression gradient-echo MR imaging in the diagnosis of ovarian cystic teratomas

Gradient-echo MR imaging (MRI) was evaluated for the diagnosis of ovarian mature cystic teratomas (MCTs). The FLASH technique was applied to T1-weighted images with and without fat suppression in 18 surgical operated patients with 19 MCTs, and findings were compared to those of conventional spin-echo (SE) T1-weighted-SE. Seventeen out of 19 MCTs were correctly diagnosed using FLASH and SE T1-weighted MR images with and without fat saturation. This study suggests that gradient-echo MRI can replace conventional SE T1-weighted MRI for the diagnosis of ovarian MCTs.

Collision tumors of the ovary associated with teratoma: clues to the correct preoperative diagnosis

PURPOSE

Collision tumors represent a coexistence of two adjacent but histologically distinct tumors without histologic admixture in an organ. The purpose of this study was to describe the imaging findings of collision tumors of the ovary associated with teratoma and to look for clues that might lead to the correct preoperative diagnosis.

METHOD

Seven pathologically proven cases of collision tumor of the ovary associated with teratoma were retrospectively reviewed. Ovarian teratomas were coexistent with mucinous cystadenoma (n = 4), borderline mucinous tumor (n = 1), mucinous cystadenocarcinoma (n = 1), and dysgerminoma (n = 1). US (n = 5), CT (n = 3), and/or MRI (n = 4) findings were evaluated.

RESULTS

In addition to the typical findings of teratoma, the mass contained a multiloculated cystic portion filled with nonfatty fluid, suggesting the coexistent epithelial tumor in five cases. In one case, the mass contained a large solid component, suggesting the possibility of collision tumor. In the remaining one case, coexistent small mucinous cystadenoma could not be identified.

CONCLUSION

Preoperative imaging for ovarian teratoma revealed a collision tumor in six of seven cases. The possibility of a collision tumor should be considered when an ovarian teratoma has imaging findings that cannot be explained solely by an ovarian teratoma.

CT features of torsion of benign cystic teratoma of the ovary

PURPOSE

The purpose of this work was to evaluate the usefulness of CT scans for distinguishing torsed from uncomplicated benign cystic teratoma (BCT).

METHOD

Retrospective analysis was performed in 14 torsed BCTs (14 patients) and in 23 uncomplicated BCTs (20 patients) for comparison. The features on CT scans were compared to the pathologic findings.

RESULTS

CT findings indicating torsed BCT were the presence of eccentric wall thickening of >1 cm, peritumoral infiltration, and presence of enlarged solid tubal mass adjacent to the uterus (p < 0.05).

CONCLUSION

The present study suggests that CT is useful in differentiating torsed from uncomplicated BCT. Although CT findings are not specific for some patients, detection of certain CT findings could increase the diagnostic accuracy.

Sonographic features of incidentally detected, small, nonpalpable ovarian dermoids

PURPOSE

We describe the transvaginal sonographic features of incidentally detected, small, nonpalpable ovarian dermoid cysts.

METHODS

A total of 38 small (less than 3 cm in diameter), nonpalpable, incidentally discovered ovarian dermoids in 35 women were retrospectively reviewed; 3 patients had small bilateral lesions, and 7 had a small ovarian dermoid detected during preoperative evaluation of a symptomatic, large, contralateral lesion.

RESULTS

Transvaginal sonography permitted identification of all 38 dermoids, whereas abdominal sonography detected only 22 of the lesions. Three main structural patterns were observed with transvaginal sonography: (1) 20 of 38 lesions had a solid, hyperechoic appearance, either homogeneous (11) or heterogeneous (9); (2) a fluid-filled area with a hyperechoic focus in its wall was seen in 10 cases; and (3) a mixed pattern, with solid and liquid areas, was seen in 8 cases. Calcifications were appreciated in 7 lesions. Acoustic shadowing was noted in 30 cases, either as a shadow posterior to the hyperechoic portion of the mass or as an edge shadow lateral to the lesion. Doppler studies were obtained for 20 lesions but proved inconclusive: 4 mixed-pattern dermoids had a few internal signals with a low resistance pattern; in the remaining cases, there were signals at the periphery of the cysts, but it could not be determined whether these were from vessels within the lesions or from vessels in the surrounding ovarian parenchyma. Surgery confirmed benign cystic dermoids in all 38 cases.

CONCLUSIONS

Sonographically, small ovarian dermoids have a variety of textural patterns quite similar to those encountered in large, symptomatic lesions. The increased resolution capabilities provided by transvaginal sonography allow incidental detection of previously unsuspected dermoids and permit identification of their nature.

Squamous cell carcinoma arising in a mature teratoma with metastasis to the urinary bladder

We describe a patient with squamous cell carcinoma arising in a mature teratoma. Magnetic resonance (MR) images revealed a solid lobulated mass attached to the ovarian cyst containing a fat-fluid level. The solid component with extension into pelvic fat showed as hypointensity on T2-weighted MR images with good enhancement. A metastatic tumor to the urinary bladder was also demonstrated.

Appendicitis and its mimickers

Unenhanced helical CT is an accurate technique for the evaluation of patients with suspected acute appendicitis. This non-operator-dependent examination can be performed without the risk of intravenous contrast material or the delay associated with the use of oral and rectal contrast material. This article reviews the unenhanced helical CT findings of acute appendicitis and those entities that commonly mimic acute appendicitis clinically.