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

Ovarian-adnexal reporting and data system ultrasound evaluation and pathological characteristics of ovarian collision tumor

BACKGROUND

Collision tumor are neoplasms, including two histologically distinct tumors that coexist in the same mass without histological admixture. The incidence of collision tumor is low and is rare clinically.

AIM

To investigate ultrasound images and application of ovarian-adnexal reporting and data system (O-RADS) to evaluate the risk and pathological characteristics of ovarian collision tumor.

METHODS

This study retrospectively analyzed 17 cases of ovarian collision tumor diagnosed pathologically from January 2020 to December 2023. All clinical features, ultrasound images and histopathological features were collected and analyzed. The O-RADS score was used for classification. The O-RADS score was determined by two senior doctors in the gynecological ultrasound group. Lesions with O-RADS score of 1-3 were classified as benign tumors, and lesions with O-RADS score of 4 or 5 were classified as malignant tumors.

RESULTS

There were 17 collision tumors detected in 16 of 6274 patients who underwent gynecological surgery. The average age of 17 women with ovarian collision tumor was 36.7 years (range 20-68 years), in whom, one occurred bilaterally and the rest occurred unilaterally. The average tumor diameter was 10 cm, of which three were 2-5 cm, 11 were 5-10 cm, and three were > 10 cm. Five (29.4%) tumors with O-RADS score 3 were endometriotic cysts with fibroma/serous cystadenoma, and unilocular or multilocular cysts contained a small number of parenchymal components. Eleven (64.7%) tumors had an O-RADS score of 4, including two in category 4A, six in category 4B, and three in category 4C; all of which were multilocular cystic tumors with solid components or multiple papillary components. One (5.9%) tumor had an O-RADS score of 5. This case was a solid mass, and a small amount of pelvic effusion was detected under ultrasound. The pathology was high-grade serous cystic cancer combined with cystic mature teratoma. There were nine (52.9%) tumors with elevated serum carbohydrate antigen (CA)125 and two (11.8%) with elevated serum CA19-9. Histological and pathological results showed that epithelial-cell-derived tumors combined with other tumors were the most common, which was different from previous results.

CONCLUSION

The ultrasound images of ovarian collision tumor have certain specificity, but diagnosis by preoperative ultrasound is difficult. The combination of epithelial and mesenchymal cell tumors is one of the most common types of ovarian collision tumor. The O-RADS score of ovarian collision tumor is mostly ≥ 4, which can sensitively detect malignant tumors.

Collision Tumor of the Ovary: Adult Granulosa Cell Tumor and Mesonephric-like Adenocarcinoma

Collision tumors of the ovaries are rare, with only a few reports in the literature. Adult granulosa cell tumors are a relatively common primary tumor component of previously reported collision tumors. The combination of serous and mucinous tumors with adult granulosa cell tumors has been reported in several cases. On the other hand, mesonephric-like adenocarcinomas are rare neoplasms that commonly arise in the uterine corpus and ovaries. In this report, we present the case of a collision tumor composed of an adult granulosa cell tumor and mesonephric-like adenocarcinoma of the ovary in a 63-year-old woman. The initial magnetic resonance imaging findings showed a cystic mass with an internal hemorrhage, which suggested an adult granulosa cell tumor, and a solid mass with different enhancements. Microscopically, the tumor had two distinct components: An adult granulosa cell tumor and a mesonephric-like adenocarcinoma. Recognizing collision tumors consisting of slow-growing and aggressive tumors may prove beneficial in future diagnostic and treatment strategies.

Mature cystic teratoma without intratumoral fat: A diagnostic dilemma

Teratomas are the most common benign ovarian neoplasms in young women. Typical computed tomography imaging findings include fat, fat fluid level, tooth or calcification, rokitansky nodule, floating balls sign, and tufts of hair. They can have unusual imaging features leading to diagnostic dilemmas. Studies have shown the presence of intratumoral fat to be specific to ovarian cystic teratoma. However, there are reports in the literature of mature cystic teratoma that do not contain fat in the lumen of the cyst which can hinder an accurate diagnosis. They can be associated with various complications like torsion, rupture, malignant transformation, infection, and autoimmune hemolytic anemias. Presented here is a case of mature cystic teratoma without visible intracystic fat which underwent torsion.

O-RADS Ultrasound Version 1: A Scenario-Based Review of Implementation Challenges

The Ovarian-Adnexal Reporting and Data System (O-RADS) ultrasound (US) risk stratification and management system was first published by the American College of Radiology in 2020. It provides standardized terminology for evaluation of ovarian and adnexal masses, aids risk stratification, and provides management guidelines for different categories of lesions. This system has been validated by subsequent research and found to be a useful diagnostic and management tool. However, as noted in the system's governing concepts, in some clinical scenarios, such as patients with acute symptoms or with a history of ovarian malignancy, O-RADS US does not apply, or the system's standard management may be adjusted. Additional scenarios, such as an adnexal mass in pregnancy, present challenges in the application of O-RADS US to assist diagnosis and management. The purpose of this article is to highlight 10 clinical scenarios in which O-RADS US version 1 may not apply, may be difficult to apply, or may require modified management. Additional scenarios in which O-RADS US can be appropriately applied are also described.

Ultrasound Findings and O-RADS Malignancy Risk Stratification of Ovarian Collision Tumors

OBJECTIVES

To describe the ultrasonographic signs of ovarian collision tumors and evaluate the malignancy risk using the O-RADS system.

METHODS

This was a retrospective analysis of 25 ovarian collision tumors from 8739 patients between May 2010 and January 2020. All clinical characteristics, ultrasound images, and histological findings were collected and analyzed. Using the O-RADS lexicon descriptors, the O-RADS score was determined by two senior doctors. Lesions with O-RADS scores of 1 to 3 were classified as benign tumors, and lesions with O-RADS scores of 4 to 5 were classified as malignant tumors.

RESULTS

The mean age of the 25 patients was 30.4 years. Histological findings showed that all tumors were a combination of mature cystic teratomas and cystadenomas/cystadenocarcinomas. There were 11 benign tumors of O-RADS 2 or 3, including 3 uniocular cysts, 3 dermoid cysts, and 5 dermoid cysts with an anechoic fluid cavity. There were 12 benign tumors of O-RADS 4, including 3 uniocular-multilocular cysts with solid components, 2 multilocular cysts with irregular walls, and 8 multilocular cysts with dermoid sacs. One borderline tumor of O-RADS 4 was a multilocular cyst with irregular septation. One malignant tumor of O-RADS 5 was a multilocular cystic tumor with solid components and ascites.

CONCLUSIONS

The most common ovarian collision tumor was the coexistence of a mature cystic teratoma and a cystadenoma. The O-RADS system was able to sensitively detect malignant tumors in this series. A typical dermoid cyst with an anechoic cavity or a multilocular cyst with a dermoid sac may signify a benign collision tumor.

Malignant degeneration of mature cystic teratoma of the ovary with small bowel metastasis incidental serous cystadenoma collision tumor of the right ovary

Mature Cystic Ovarian Teratoma (MCOTs) are the most common benign ovarian neoplasms, representing around 20% of all ovarian neoplasms with middle age women representing the majority of patients. They usually include two germ cell layers being well differentiated and rarely they demonstrate malignant transformation with squamous cell carcinoma being the most common malignant transformation. In our case, we report an interesting case of a 45 years old lady who was unfortunate to have a MCOT with malignant degeneration and distant metastasis. We concluded that MCOT malignant degeneration is rare, however, if not caught early, mortality can be high.

MCOT, Ovary, Small Bowel, Teratoma, Collision tumor

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.

Mature Ovarian Teratoma: Atypical Imaging

The incidence of a mature ovarian teratoma ranged from 20% to 30% of pediatric ovarian tumors (Sabaa et al., 2009), which is composed of well-differentiated tissues that derive from all three germ cell layers (ectoderm, mesoderm, and endoderm); it is one of the most common benign ovarian neoplasms. In this case report, we discuss a 9-year-old female patient who presented with abdominal pain and distended abdomen, for which she had an abdominal ultrasound and magnetic resonance imaging. The histopathological exam, after a laparotomy, showed a mature ovarian teratoma.

Mature cystic ovarian teratoma without intracystic fat: Case report with the "fat within the wall" sign

Mature cystic teratoma is the most common ovarian neoplasm among young females. Diagnosed through radiological imaging as it exhibits typical radiological features; typically, fat. However, complete cystic teratoma without visible fat is a very rare and challenging diagnosis. It is difficult to distinguish it from malignant neoplasm, due to the presence of enhancing components, for example, Rokitansky nodule and the presence of diffusion restriction from keratinized products. We present a case of an incidental mature cystic teratoma without visible intracystic fat, where the correct diagnosis based on imaging was failed. Mature cystic teratoma was then confirmed upon histologic examination.

Collision Tumors in Ovary: Case Series and Literature Review

Histologically distinct tumors that coexist in an organ without any histological admixture at their interface are denominated collision tumors. We report 3 cases of colliding mature cystic teratoma with mucinous cystadenoma and a case of mature cystic teratoma colliding with benign Brenner tumor in the ovary. We also provide a literature review based on 35 previously published ovarian collision cases. Ovarian tumors from all classes, benign, borderline and malignant lesions may collide. Both our case series and the literature review indicate that ovarian tumor collisions tend to be clinically and ultrasonographically/radiologically unrecognized. The awareness among surgeons, radiologists and pathologists of this rare phenomenon and histological recognition are crucial in order to offer adequate treatment to patients. There is a need to identify novel and more specific imaging clues pointing towards collision tumors in the ovary.

Squamous cell carcinoma arising in a partially ruptured giant mature cystic teratoma: A case report

Mature cystic teratomas are the most common ovarian germ cell tumors and represent 70% of the benign ovarian tumors occurring in women under age 30. In less than 2% of cases, these tumors can transform into malignancies. Squamous cell carcinoma arises most frequently from these tumors (in 80% of cases). Intra-peritoneal rupture accounts for approximately 1%-2% of cystic teratoma complications with most ruptures occurring either intraoperatively during laparoscopic surgery or due to trauma. This case report describes the common presentation, imaging, and pathologic findings of a mature cystic teratoma with 2 uncommon associated complications.

Primary Central Nervous System Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type Colliding with Meningioma

BACKGROUND

Collision tumors are defined as coexistence of 2 histologically different neoplasms occurring in the same anatomic location. Such co-occurrence of tumors in the brain is uncommon. To our knowledge, meningioma colliding with extranodal natural killer/T-cell lymphoma has not been described previously.

CASE DESCRIPTION

A 50-year-old man presented with a 1-year history of progressive memory decline and 2 weeks of drowsiness, bradykinesia, and aphasia. Magnetic resonance imaging revealed a heterogeneously enhanced mass beside the left frontal cerebral falx resulting in midline shift. The left frontal lobe mass was resected. Pathologic examination showed the tumor consisted of whorled spindle cells and diffuse medium-sized lymphoid cells. The spindle cells were positive for epithelial membrane antigen and negative for S-100. The lymphoid cells expressed CD3ε, CD56, TIA-1, and granzyme B. Epstein-Barr virus encoded small RNAs were detected by in situ hybridization. No monoclonal T-cell receptor gamma gene rearrangement was detected. Four weeks after surgery, the patient was treated with polychemotherapy and intrathecal methotrexate, but he died 2 months later.

CONCLUSIONS

This is the first report of a unique brain collision tumor consisting of a meningioma and an extranodal natural killer/T-cell lymphoma. Diagnosis depends on histopathology. Awareness of this entity is important to distinguish it from other intracranial tumors.

Ovarian collision tumors: imaging findings, pathological characteristics, diagnosis, and differential diagnosis

Collision tumors are uncommon neoplasms in which elements of differing histologic origins coexist in a single mass. Ovarian collision tumors are a rare subtype of such lesions. The identification of collision tumors by radiologic examinations is essential to ensure that comprehensive biopsies are performed to guide appropriate treatments. According to the clinical and imaging findings of 12 patients and reviews of previous studies, ovarian collision tumors are mixtures of different combinations of epithelial tumors, germ cell tumors, and sex-cord-stromal tumors. The smaller tumors are usually located inside ("nested tumor") or on the wall ("back to back") of the larger tumors. Each type of ovarian collision tumors presents specific CT/MRI features in accordance with their histologic origins and collision patterns. Knowledge of the imaging features of ovarian collision tumors is crucial to aid preoperative diagnostic accuracy.

Pancreatic Collision Tumor of Ductal Adenocarcinoma and Neuroendocrine Tumor

A pancreatic collision tumor is a rare entity that can be challenging to diagnose. We present a very rare case of a pancreatic collision tumor composed of both a neuroendocrine tumor and a ductal adenocarcinoma. Preoperative diagnosis was clinically challenging because both the radiology and fine-needle biopsy were consistent with a typical neuroendocrine mass. However, gross examination of the mass postoperatively revealed neuroendocrine cells with rare foci of ductal adenocarcinoma without a transition zone. Awareness of this entity is important so that medical practitioners consider pursuing surgical management of pancreatic lesions that otherwise would be managed exclusively with surveillance.

Combination of clinical and laboratory characteristics may serve as a potential diagnostic marker for torsion on mature cystic teratomas

Objective

The objective of this study was to evaluate clinical and laboratory characteristics of torsion on mature cystic teratomas (MCTs). In addition, we examined whether these factors could be helpful in diagnosing MCT torsion.

Methods

A retrospective medical record review was conducted for 384 patients who had undergone surgery and histologically verified ovarian MCTs at single university hospital between July 2006 and May 2017. Patients with or without torsion groups were compared with respect to clinical presentation, laboratory findings and surgical course. In addition, statistically significant indicators of the factors were additionally evaluated for diagnostic value.

Results

White blood cell (WBC) count, neutrophil count, neutrophil to lymphocyte (N/L) ratio, and tumor size were higher in the torsion group (n=24) than in the control group (n=360; P≤0.005 for all). The age was younger in the torsion group than in the control (P=0.009). In the area under the curve (AUC) of the 5 factors obtained by univariate and multivariate logistic regression, the age was 0.657, the WBC count was 0.838, the neutrophil count was 0.806, the N/L ratio was 0.725, and the cyst size was 0.705. Receiver operating characteristic analysis indicated that the AUC for the combined use of age, WBC count, neutrophil count, N/L ratio, and tumor size was 0.898 (95% confidence interval, 0.833–0.962; P<0.001).

Conclusion

The combined measurement of age, WBC count, neutrophil count, N/L ratio, and tumor size may be used as a potential diagnostic marker for the torsion on MCTs.

Torsion of Collision Tumor: Dermoid Cyst and Fibrothecoma with Postmenopausal Bleeding

The term collision tumor refers to the coexistence of two adjacent but histological distinct tumors with no histological admixture at the interface. Collision tumors involving ovaries are extremely rare. A collision tumor composed of a dermoid cyst and fibrothecoma is extremely rare in menopausal women. The mechanism of the development of collision tumor is uncertain. During clinical evaluation, differentiation of characters of these ovarian tumors is important to decide appropriate treatment strategies and for good prognosis. We report an unusual clinical manifestation of the torsion of a dermoid cyst and fibrothecoma in the right ovary with postmenopausal bleeding.

Ovarian malignant germ cell tumors: cellular classification and clinical and imaging features

Ovarian malignant germ cell tumors (OMGCTs) are heterogeneous tumors that are derived from the primitive germ cells of the embryonic gonad. OMGCTs are rare, accounting for about 2.6% of all ovarian malignancies, and typically manifest in adolescence, usually with abdominal pain, a palpable mass, and elevated serum tumor marker levels, which may serve as an adjunct in the initial diagnosis, monitoring during therapy, and posttreatment surveillance. Dysgerminoma, the most common malignant germ cell tumor, usually manifests as a solid mass. Immature teratomas manifest as a solid mass with scattered foci of fat and calcifications. Yolk sac tumors usually manifest as a mixed solid and cystic mass. Capsular rupture or the bright dot sign, a result of increased vascularity and the formation of small vascular aneurysms, may be present. Embryonal carcinomas and polyembryomas rarely manifest in a pure form and are more commonly part of a mixed germ cell tumor. Some OMGCTs have characteristic features that allow a diagnosis to be confidently made, whereas others have nonspecific features, which make them difficult to diagnose. However, imaging features, the patient's age at presentation, and tumor markers may help establish a reasonable differential diagnosis. Malignant ovarian germ cell tumors spread in the same manner as epithelial ovarian neoplasms but are more likely to involve regional lymph nodes. Preoperative imaging may depict local extension, peritoneal disease, and distant metastases. Suspicious areas may be sampled during surgery. Because OMGCTs are almost always unilateral and are chemosensitive, fertility-sparing surgery is the standard of care.

Ovarian mucinous cystadenoma coexisting with benign Brenner tumor: MR imaging findings

PURPOSE

The purpose of this study was to describe the MR imaging findings of ovarian mucinous cystadenomas coexisting with benign Brenner tumors.

MATERIALS AND METHODS

MR images with a 1.5-T unit obtained in five consecutive patients (age range, 51-72 years; mean age, 61 years) with surgically confirmed ovarian mucinous cystadenomas coexisting with benign Brenner tumors were retrospectively reviewed for the presence, configuration, and signal intensity of cystic and solid components of the lesions.

RESULTS

Tumors ranged in size from 7.5 to 22.1 cm (mean, 13.5 cm). In four patients (80%), the size of mucinous cystadenoma (range 6.4-22.1 cm; mean, 12.5 cm) was larger than that of Brenner tumor (range 0.2-9.1 cm; mean, 2.8 cm). All patients (100%) had cystic, and three (60%) had solid components. Four patients (80%) showed multilocular cystic, and one (20%) showed unilocular cystic appearance. MR imaging findings were classified into three patterns: (1) a bulky solid mass adjacent to the cystic component, (2) a mural nodule at the periphery of the cystic component, and (3) a cystic component without a detectable solid component. All four multilocular cystic areas exhibited "stained glass" appearances on both T1- and T2-weighted images, and all three solid areas showed homogeneous hypointensity on T2-weighted images.

CONCLUSION

Mucinous cystadenomas were often larger than the coexisting benign Brenner tumors. Mucinous cystadenomas coexisting with benign Brenner tumors should be considered when multilocular or unilocular cystic components are accompanied by homogeneously hypointense solid components on T2-weighted images.

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.

Collision tumor: serous cystadenocarcinoma and dermoid cyst in the same ovary

INTRODUCTION

Collision tumor means the coexistence of two adjacent, but histologically distinct tumors without histologic admixture in the same tissue or organ. Collision tumors involving ovaries are extremely rare.

CASE

We present a case of 45-year-old parous woman with a left dermoid cyst, with unusual imaging findings, massive ascites and peritoneal carcinomatosis. The patient underwent cytoreductive surgery. The histopathology revealed a collision tumor consisting of an invasive serous cystadenocarcinoma and a dermoid cyst.

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.

Ovarian mature teratomas with mucinous epithelial neoplasms: morphologic heterogeneity and association with pseudomyxoma peritonei

Mucinous epithelial neoplasms arising in association with mature teratomas are a heterogeneous group of tumors, but with the exception of a single recent study, their full histologic spectrum, detailed immunophenotype, and association with classic pseudomyxoma peritonei (PMP) have not been fully studied. The morphologic, immunohistochemical, and clinical features of 42 patients with mucinous epithelial tumors arising in association with mature ovarian teratomas were evaluated. The patients' ages ranged from 17 to 66 years (mean, 39 y). Tumor size ranged from 5.5 to greater than 200 cm. Most teratoma-associated mucinous tumors were unilateral, although 1 patient harbored bilateral mucinous tumors in association with bilateral teratomas. In all cases, the teratomatous component consisted of mature elements. Using the 2003 World Health Organization criteria for ovarian intestinal type mucinous neoplasms, 17 (40%) were classified as mucinous cystadenoma, 16 (38%) as intestinal-type mucinous epithelial neoplasm of low malignant potential (IM-LMP), 4 (10%) as intraepithelial carcinoma (IEC), and 5 (12%) as invasive mucinous carcinoma. Mucinous cystadenomas had a varied epithelial lining consisting of lower gastroenteric, gastric foveolar, or müllerian appearance. In contrast, the IM-LMP, IEC, and invasive carcinoma cases had a more uniform lower gastroenteric histology. For mucinous cystadenomas, a cytokeratin (CK) 7+/CK20- phenotype (5/13; 38%) was equally as common as a CK7-/CK20+ phenotype (5/13; 38%), with the remaining cases coexpressing both keratins (CK7+/CK20+: 3/13; 23%). In contrast, IM-LMP, IEC, and invasive adenocarcinomas more frequently had a CK7-/CK20+ phenotype (56%, 50%, and 100%, respectively). A CK7+/CK20-phenotype was rare in these later 3 morphologic groups (6%). Of the 42 total cases, 55% had pseudomyxoma ovarii and 24% had classic PMP (1 cystadenoma, 6 IM-LMP, and 3 invasive carcinomas), whereas 5% had more localized accumulations of peritoneal mucin (both IM-LMP). Pathologic evaluation of the peritoneum in these 12 cases revealed 6 with acellular mucin alone, 3 with low-grade mucinous epithelium (all 3 with ovarian IM-LMP), and 3 with high-grade mucinous carcinomatosis (all 3 with ovarian mucinous adenocarcinoma). No appendiceal lesions were identified. Follow-up was available in 48% of patients (mean, 61 mo). The only adverse outcomes occurred in the 3 patients with ovarian carcinoma and associated peritoneal carcinomatosis. We report that a significant proportion of mucinous tumors associated with mature ovarian teratomas present with clinical PMP, which in most cases is associated with IM-LMP. PMP in this setting may harbor microscopic intra-abdominal low-grade mucinous epithelium that is histologically and immunophenotypically similar to that typically seen in appendiceal-related PMP. Pseudomyxoma ovarii is common in this setting, particularly in tumors with IM-LMP histology, but pseudomyxoma ovarii is not predictive of PMP. Ovarian teratoma-associated benign and IM-LMP mucinous neoplasms with microscopic peritoneal low-grade mucinous epithelium do not seem to be at significant risk for intra-abdominal recurrence, but numbers are few and follow-up is limited. In contrast, teratomas with an invasive carcinomatous component and microscopic peritoneal carcinomatosis follow an aggressive clinical course.

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.

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.

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.