CT of benign cystic teratomas

Mature cystic teratoma overlapping with giant serous cystadenoma of the ovary: A case report

Ovarian lesions represent a diagnostic challenge for the radiologist and should be approached according to the patient's age, menstrual cycle, and imaging characteristics. These lesions can be cystic, mixed, or solid-predominant structures. Generally, the occurrence of benign lesions surpasses that of malignant ones at a ratio of 3:1. However, within infantile and juvenile age groups, this becomes an infrequent occurrence, making up only about 5% of ovarian tumor cases. This case report sheds light on a unique scenario involving a pediatric patient who harbored 2 benign tumors simultaneously: a mature cystic teratoma and a serous cystadenoma.

Computed tomographic findings in a canine ovarian teratoma

A 2-year-old, intact female, Labrador Retriever was referred for progressive abdominal distension, assessed by emergency clinicians as being extrauterine in origin on AFAST. Abdominal radiographs and ultrasound identified a large, lobulated, partially mineralized, soft tissue, mid-abdominal mass and gravid uterus. Contrast-enhanced CT identified a mixed fat to soft tissue attenuating mass with a complex internal mineralized matrix, heterogeneous contrast enhancement, receiving blood from the left ovarian artery. Histology confirmed a left ovarian teratoma, diffuse endometrial hyperplasia, and fetal implantation. The patient had a good post-operative outcome for 2 years, but was later diagnosed with primary cranial mediastinal neuroendocrine carcinoma.

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.

Ultrasound and alternative multimodality imaging of intra-abdominal and pelvic cystic masses in the newborn

Introduction: Ultrasound is used commonly to detect and diagnose intra-abdominal and pelvic cystic masses in the newborn as it is easily available, relatively low cost, and non-invasive. Discussion: The diagnosis can be made or narrowed down by determining the location, size, sonographic features, organ involvement, and internal vascularity. The differential diagnoses include hydronephrosis, multicystic dysplastic kidney, adrenal haemorrhage, cystic teratomas, ovarian cysts, enteric cysts, meconium cysts, and liver haemangiomas. With the appropriate radiological knowledge, the ultrasound practitioner can help obtain an accurate diagnosis. Conclusion: This pictorial essay will familiarise the reader with the different common causes of intra-abdominal and pelvic masses detected on ultrasound through a wide range of conditions. The role of ultrasound in the evaluation of these conditions will be discussed and alternative imaging correlates will be offered.

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.

Imaging Patterns of Intratumoral Calcification in the Abdominopelvic Cavity

Intratumoral calcification is one of the most noticeable of radiologic findings. It facilitates detection and provides information important for correctly diagnosing tumors. In the abdominopelvic cavity, a wide variety of tumors have calcifications with various imaging features, though the majority of such calcifications are dystrophic in nature. In this article, we classify the imaging patterns of intratumoral calcification according to number, location, and morphology. Then, we describe commonly-encountered abdominopelvic tumors containing typical calcification patterns, focusing on their differentiable characteristics using the imaging patterns of intratumoral calcification.

Mature cystic teratoma of the ovary: a cutting edge overview on imaging features

Mature cystic teratoma (MCT) is the most common neoplasm of the ovary and includes at least two well- differentiated germ cell layers. Different combinations of mature tissue derivatives with varying arrangements in the tumour cause a wide spectrum of radiological presentation ranging from a purely cystic mass to a complex cystic mass with a considerable solid component. In different imaging modalities, each radiological feature reflects a specific pathologic equivalent that forms because of diverse compositions of histological components. Understanding uncommon findings as well as the classic signs with basic knowledge of pathological equivalents permits a more accurate diagnosis and guides adequate treatment. In this review, radiological features of MCT in different imaging modalities (US, CT, MR imaging) including specific signs and useful radiological artefacts with brief emphasis on pathological basics are discussed.

Teaching points

• Ovarian mature cystic teratomas (MCTs) have a wide spectrum of radiological presentation.

• Each radiological feature of MCT reflects a specific pathologic equivalent.

• Understanding radiological signs with basic knowledge of pathology can permit a more accurate diagnosis.

Computed Tomography of Anterior Mediastinal Tumors

Computed tomographic (CT) features in 10 patients with germ cell tumor of the mediastinum and 15 with thymoma were compared with surgically resected specimens. The CT findings of the internal structure of tumors were the most important factor for specific diagnosis. Germ cell tumors showed a round mass without distinct lobulation, frequently with calcification appearing as a globular shape, and especially in benign tumors as an arched shape along the wall. Homogeneous low density masses (near-water) with a thick wall were benign and non-homogeneous density masses (a mixture of near-water and soft tissue) were malignant. Thymoma usually showed a solid mass with lobulation and sometimes had an eggshell type of calcification in the tumor. Therefore, CT is of importance in the diagnosis of anterior mediastinal masses.

Imaging Features of Various Adrenal Neoplastic Lesions on Radiologic and Nuclear Medicine Imaging

OBJECTIVE

The purpose of this review is to describe the features of diverse adrenal neoplastic lesions on radiologic and nuclear medicine imaging.

CONCLUSION

Various neoplastic lesions with or without malignant potential can occur in the adrenal gland. Knowledge of imaging features of adrenal lesions on radiologic and nuclear medicine imaging will facilitate differential diagnosis and assessment of malignant potential.

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.

Patterns of misinterpretation of adnexal masses on CT and MR in an academic radiology department

RATIONALE AND OBJECTIVES

The aim of this study was to assess potential quality assurance (QA) issues in the diagnosis and characterization of adnexal masses on pelvic computed tomographic (CT) and magnetic resonance (MR) imaging studies.

MATERIALS AND METHODS

Images from 128 women who had oophorectomies during a 16-month period with CT and/or MR studies within 5 years of surgery (145 CT scans from 103 women and 49 MR studies from 42 women, with 17 having both MR and CT studies) were reviewed by three radiologists who assigned QA scores of 0 (no QA issue), 1 (minor issue with minimal impact on clinical care), or 2 (major issue with potential impact on clinical care). The difficulty of diagnosis was assigned a score of 0 (very difficult diagnosis to make), 1 (difficult but possible to make the diagnosis), or 2 (diagnosis should be made). The incidence of adnexal QA issues was calculated using total CT and MR pelvic examinations performed on women during the interval.

RESULTS

Twenty-nine QA issues were identified in 28 women in 17 of 145 CT studies (11.7%) and 12 of 49 MR examinations (24.5%) in women having adnexal surgery (17 of 11,194 [0.15%] of female pelvic CT studies and 12 of 603 [2.0%] of female pelvic MR studies performed in the time interval). Issues included missed lesions, lesions misidentified as leiomyomas, fat described in the lesion but not seen histologically, postmenopausal status of patient not considered, ultrasound correlation not recommended, and confusion of right and left sides.

CONCLUSION

Errors in CT and MR studies regarding the diagnosis and characterization of adnexal masses in a highly enriched population of women undergoing adnexal surgery are common. Knowledge of the types of QA issues found in CT and MR studies of adnexal masses should aid in decreasing future errors.

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.

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.

Uncommon adrenal masses: CT and MRI features with histopathologic correlation

Adrenal glands are common sites of diseases. With dramatically increased use of computed tomography (CT) and magnetic resonance (MR) imaging, more and more uncommon adrenal masses have been detected incidentally at abdominal examinations performed for other purposes. In this article, uncommon adrenal masses are classified as cystic masses (endothelial cysts, epithelial cysts, parasitic cysts, and pseudocysts), solid masses (ganglioneuroma, ganglioneuroblastoma, extramedullary plasmacytoma (EMP), neurilemmoma, and lymphoma), fat-containing masses (myelolipoma, teratoma), and infectious masses (tuberculoma), and the imaging features of these uncommon masses are demonstrated. Although most of these lesions do not have specific imaging features, some fat-containing masses and cystic lesions present with characteristic appearances, such as myelolipoma, teratoma, and hydatid. Combination with histopathologic characteristic of these uncommon masses of adrenal gland, radiological features of these lesions on CT and MR imaging can be accurately understood with more confidences. Moreover, CT and MRI are highly accurate in localization of uncommon adrenal masses, and useful to guide surgical treatments.

"Primary" benign retroperitoneal and intraspinal dumbbell-shaped cystic teratoma: case report

STUDY DESIGN

A case of unusual dumbbell-shaped cystic teratoma is presented.

OBJECTIVES

To investigate and describe an unusual case of retroperitoneal cystic teratoma with spinal invasion in an adult. The image findings, minimally invasive surgical procedures, and clinical outcome were discussed, and the literature was reviewed.

SUMMARY OF BACKGROUND DATA

Primary benign cystic teratomas of the retroperitoneum are rare. Extension of these lesions into the spinal canal is more rare. In this report, by presenting a case of cystic teratoma with such extension, the origin of the tumor, and the value of computerized tomography and magnetic resonance imaging (MRI) in the preoperative diagnosis and surgical approach for the extended lesion are discussed.

METHODS

The patient was a 24-year-old female who had had low back pain with bilateral sciatica for 2 months. Preoperative computerized tomography and MRI of the thoracic and lumbar spines showed a dumbbell-shaped tumor, with the solid part residing in the right retroperitoneum near the neuroforamen of the L2-L3 spines and the cystic part extending into the spinal canal. By performing right L2-L4 hemilaminectomies with a mini retroperitoneal approach, the tumor was removed en bloc in one stage.

RESULTS

Diagnosis of cystic teratoma was confirmed by pathologic examination. The patient recovered well without any neurologic deficits, and recurrence of tumor has not been found for 9 years postoperatively.

CONCLUSIONS

Total surgical removal of tumor is an ideal treatment for retroperitoneal and intraspinal dumbbell-shaped cystic teratoma. MRI displays the precise location, morphology, and adjacent structures of the tumor, which provide for better preoperative planning and more complete removal of tumor with less neurologic damage.

Trichoptysis caused by intrapulmonary teratoma: computed tomography and magnetic resonance imaging findings

We describe a 9-year-old child with a history of trichoptysis caused by intrapulmonary teratoma and we present the CT and MRI findings of the teratoma. A heterogeneous mass containing cystic and solid elements was detected on both CT and MRI scans. Histopathological examination confirmed the diagnosis of teratoma. Teratomas arising from lung parenchyma, as in this case, are extremely rare in childhood. In the thoracic region, the most common localization of teratomas is the anterior mediastinal compartment. We also discuss the CT and MRI findings and the differential diagnosis of teratomas.

Dermoid cyst in bony pelvis that coexists with pheochromocytoma: report of a case and review of the literature

A 42-year-old man presented with right lower quadrant abdominal pain and dysuria. The bladder was displaced to the right side of the pelvis in excretory urography. Abdominal CT revealed a mass in right adrenal gland, measuring 8 cm in diameter. There was also a cystic mass; filling left half of the bony pelvis and displacing bladder to the right, measuring 14.5 x 10, 5 x 7 cm. The patient underwent right adrenalectomy and pelvic mass excision. Pathologic examination showed that the adrenal mass was pheochromocytoma and pelvic mass was dermoid cyst. This case is the first one in literature that an intrapelvic dermoid cyst is not derived from an organ coexists with pheochromocytoma.

Mature teratoma within the posterior mediastinum

Mature teratomas in the chest are typically located within the anterior mediastinum. The authors report a case of a mature teratoma in a young adult male with characteristic imaging features except for its location: the posterior mediastinum. On review of the literature, 3% to 8% are reported as confined to the posterior mediastinum and 13% have extension into other mediastinal compartments.

Adnexal mass evaluation in the emergency department

Female patients who have stable vital signs presenting to the emergency department with abdominopelvic pain and an adnexal mass can be extremely difficult to manage. However, by performing a rapid problem-oriented history and physical with emphasis on the age of patient, menstrual history, and pelvic exam, a detailed differential diagnosis can be compiled. With the addition of a complete blood count and HCG, if appropriate, and a CA-125 for your consultant, additional information can be obtained while a ultrasound examination is being performed. With the above information, consultation and disposition should be readily accomplished.

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.

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.

The unusual imaging appearance of primary retroperitoneal teratoma: report of a case

Primary retroperitoneal (RP) teratoma is a rare entity which has a distinctive imaging appearance. We describe herein the case of a 25-year-old man in whom a RP teratoma was found to have an extremely unusual imaging morphology by ultrasound and computed tomography (CT). The tumor was resected and histopathological examination confirmed the diagnosis of primary benign RP teratoma.

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.

Retroperitoneal lymphangioma

Five cases of retroperitoneal lymphangioma are presented. In three patients the lesions were symptomatic, with resolution of the symptoms following resection. In two elderly patients the lesions were asymptomatic. Ultrasound demonstrated masses that ranged from 4 to 15 cm in maximal extent, and which were predominantly anechoic. Two contained septations and two echogenic debris. Computed tomography demonstrated the masses to be of water density, and allowed better delineation of the lesions to adjacent structures within the anterior pararenal space. Fine needle aspiration (FNA) produces a characteristic cytology of abundant lymphocytes, which may be intermingled with macrophages. It is considered that retroperitoneal lymphangioma has characteristic imaging features that allows a presumptive diagnosis, which can be confirmed by FNA.

Fat suppression techniques in MR imaging of mature ovarian teratomas: comparison with CT

OBJECTIVE

The aim of this study is to analyze the ability of MR fat suppression techniques to characterize fat components of ovarian mature cystic teratomas (MCT) shown by CT.

SUBJECTS AND METHODS

MR images of eight MCTs of the ovary were obtained using standard sequences followed by a SPIR (spectral presaturation with inversion recovery) sequence in six cases and by Dixon sequences in two cases. In all cases correlation with CT and pathologic findings was achieved.

RESULTS

MR fat suppression sequences showed to be as accurate as CT in detecting fat inside the cystic part of the teratomas (8/8).

CONCLUSION

MR fat suppression sequences should be performed when presence of fat is suspected on images of ovarian tumors produced by standard MR sequences.

Primary ovarian tumors in the pediatric patient: CT evaluation

Primary ovarian tumors in the pediatric age group are rare with limited descriptions on computed tomography (CT). We describe the CT findings in a series of nine mature cystic teratomas, one immature teratoma, two granulosa cell tumors, and one undifferentiated small cell tumor. Four mature cystic teratomas were atypical in their CT appearance. The immature teratoma was distinguished by its large, irregular, diffusely calcified solid component. The malignant tumors were large and nearly totally solid, or if multicystic, contained a large solid component.

Let the finger linger

Retrorectal masses are rare and of insidious onset. We report a consecutive series of six such cases (males = 4, females = 2). The main presenting complaint was back pain and the most reliable physical sign was a palpable mass posteriorly on rectal examination (all cases). C T scan was the most radiologically informative investigation. Surgical intervention was undertaken using both anterior (trans-abdominal) and posterior (retrorectal) approaches. The majority of the masses excised were benign and all patients, to date, remain well.

Retroconversion of immature teratoma of the ovary: CT appearances

We have studied seven patients presenting to the Royal Marsden Hospital between 1983 and 1989 with metastatic immature teratoma of the ovary. All patients underwent initial surgery followed by combination chemotherapy and a second laparotomy. Serial CT scans were performed at 2-3 monthly intervals from diagnosis until the second laparotomy, and the results of this were correlated with the CT appearances. In six of the seven patients CT scanning demonstrated 'retroconversion' of immature malignant tumour masses to benign mature disease during treatment. CT features of maturation included increased density of mass lesions, whose margins became better circumscribed in relation to adjacent tissues, and the onset of internal calcification, with fatty areas and cystic change. These changes on CT correlated exactly with normalization of an initially raised serum tumour marker, alpha feto-protein (AFP) in all six patients. The second laparotomy revealed only mature teratoma in all patients following chemotherapy. In three patients show continued growth of the mature deposits necessitated further surgery for local pressure symptoms, but overall, none has shown malignant relapse, and all are currently well between 1 and 6 years after diagnosis. This is the first report of the CT appearances of retroconversion of immature ovarian teratoma in a series of patients, which is an important radiological diagnosis to make in order to avoid confusion with advancing malignancy. A review of the literature is presented.

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.

Infected teratoma of lower posterior mediastinum in a six-year-old boy

A six-year old boy presented with prolonged unexplained fever caused by an infected teratoma of the lower posterior mediastinum. Modern imaging, combining ultrasonography with computed tomography, enabled the correct diagnosis of topography, extension and nature of this rare lesion to be made and explained the clinical features. Follow-up CT showed regression of the abscess after antibiotics thus permitting elective surgery.

Peritonitis due to rupture of retroperitoneal teratoma: computed tomography diagnosis

Retroperitoneal benign cystic teratoma is relatively rare in adults. We report a case of traumatic rupture of primary retroperitoneal teratoma into peritoneum that produced chemical peritonitis. It was demonstrated by computed tomography, which showed fat-fluid levels in the peritoneum. We suggest that the demonstration of fat-fluid levels in the peritoneum could be a reliable sign of intraperitoneal rupture of abdominal teratoma and subsequent chemical peritonitis.

Cystic teratoma of the mesentery

Cystic teratoma is an unusual cause of mesenteric/omental cysts. A case of cystic teratoma of the mesentery in a 5-year-old girl is reported.

Posterior mediastinal cystic teratoma surrounded by fat in a 13 month old boy. Value of magnetic resonance imaging

A 13 month old boy had a large left sided posterior cystic mass initially thought to be in lung. MRI showed the cystic mass to be surrounded by fat. A benign mediastinal teratoma was removed.

Diagnostic imaging techniques in mediastinal malignancies

Mediastinal masses occur in both men and women of every age, and close to half of affected patients are asymptomatic. Screening of asymptomatic persons is not economically feasible. Symptomatic patients should be evaluated initially with posteroanterior and lateral chest radiographs. Additional imaging techniques may be required in patients suspected of having a mediastinal mass, when there is a questionable abnormality seen on chest radiographs or when local or systemic symptoms suggest a mediastinal mass. These techniques include oblique views, over-penetrated radiographs, and fluoroscopy of the chest. Computerized tomography of the chest is the imaging modality of choice for further assessment of a mediastinal mass. It can also be an important adjunct in radiotherapy portal planning. The use of other imaging modalities depends on the location of the tumor, the equipment available, and the expertise of local radiologists. In following up treated patients for disease recurrence, periodic chest radiographs are usually sufficient. Computerized tomography scans, because of their expense, should only be obtained as a baseline after completion of therapy or in patients with a suspected relapse.

Primary cysts and neoplasms of the mediastinum: recent changes in clinical presentation, methods of diagnosis, management, and results

Major changes have recently occurred in the clinical presentation, diagnosis, and management of primary lesions of the mediastinum. New diagnostic techniques and improved therapy have led to more objective preoperative diagnoses as well as better long-term results. These features are clearly demonstrated in a series of 400 consecutive patients with primary lesions of the mediastinum seen at Duke University Medical Center. Of these, 99 (25%) had a primary cystic lesion. The primary tumors included thymic neoplasms (17%), neurogenic tumors (14%), lymphoma (16%), germ cell tumors (11%), and a miscellaneous group. Malignant neoplasms were present in 166 patients (42%). The anterosuperior mediastinum was the most commonly involved site of a primary cyst or neoplasm (54%), followed by the posterior mediastinum (26%) and the middle mediastinum (20%). Symptoms were present in 62% of the patients and included chest pain (30%), dyspnea (16%), fever and chills (20%), and cough (16%). Of the lesions found on routine chest roentgenograms, 83% were benign. In contrast, 57% of the lesions in symptomatic patients were malignant. Prior to 1967, 94% of asymptomatic lesions were benign, but this figure has now decreased to 76%. Fifty percent of symptomatic patients had a malignant neoplasm before 1967 compared with 62% after that year. Newer diagnostic techniques have greatly enhanced the accuracy of the preoperative diagnosis. They include radioisotopic scanning, monoclonal antibodies, hormonal assay, electron microscopy, fine-needle aspiration biopsy, computed tomographic scans, and magnetic resonance imaging. Each has a definite role and is specifically illustrated as being quite important in this series.(ABSTRACT TRUNCATED AT 250 WORDS)

CT evaluation of mediastinal masses

CT is an important modality for imaging mediastinal masses, and certain CT attenuation features (fat, calcium, or water attenuation, contrast enhancement) are well known to suggest specific diagnoses. In a series of 132 consecutive patients with tissue-proven mediastinal masses, these specific CT features were present in only 16. We evaluated the ability of CT to differentiate soft tissue mediastinal masses based on morphology and distribution of disease. Metastatic disease and lymphoma accounted for 69% of masses in this series, and CT could not generally differentiate them. However, CT was helpful in differential diagnosis in certain settings. CT demonstration of multiple mediastinal masses when conventional radiographs showed a single mass generally excluded diagnoses such as thymoma and teratoma. CT demonstration of a single middle mediastinal mass, frequently missed by conventional radiography, made metastatic disease a much more likely diagnosis than lymphoma. Finally, CT demonstration of certain ancillary findings strongly favored a diagnosis of lymphoma (axillary adenopathy) or metastatic disease (solitary pulmonary mass, focal liver lesions, bone lesions).

Computerized tomography demonstration of an intrarenal teratoma

The computerized tomographic appearance of an intrarenal teratoma is described. The differential diagnoses, especially from Wilms tumor, are discussed.