18F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

An Unusual Case of Esophageal Carcinosarcoma on 18F-FDG PET/CT

ABSTRACT

Carcinosarcoma of the esophagus is a rare malignant neoplasm. Here, we report a case of esophageal carcinosarcoma with lymphatic and pulmonary metastases on 18F-FDG PET/CT in a 64-year-old woman.

Uterine Carcinosarcoma: A Case Report and Literature Review

Uterine carcinosarcomas are rare and extremely aggressive undifferentiated carcinomas which include both carcinomatous and sarcomatous elements. A 52-year-old female presented with heavy irregular menstrual bleeding for several years and new right elbow pain and swelling. Ultrasound and computed tomography showed a large uterine mass with regional and distant metastatic lymphadenopathy and suspicious findings of osseous metastasis to the right elbow. A biopsy confirmed uterine carcinosarcoma, and the patient underwent chemotherapy and then surgical resection of the uterine mass with palliative radiotherapy of the right elbow. The postoperative imaging showed new metastasis, and the patient was scheduled to start on immunotherapy. Considering the highly invasive nature of uterine carcinosarcomas, timely detection of this cancer using characteristic imaging and pathology findings is of extreme importance to improve the patient's survival.

How to differentiate uterine leiomyosarcoma from leiomyoma with imaging

Uterine leiomyomas, the most frequent benign myomatous tumors of the uterus, often cannot be distinguished from malignant uterine leiomyosarcomas using clinical criteria. Furthermore, imaging differentiation between both entities is frequently challenging due to their potential overlapping features. Because a suspected leiomyoma is often managed conservatively or with minimally invasive treatments, the misdiagnosis of leiomyosarcoma for a benign leiomyoma could potentially result in significant treatment delays, therefore increasing morbidity and mortality. In this review, we provide an overview of the differences between leiomyoma and leiomyosarcoma, mainly focusing on imaging characteristics, but also briefly touching upon their demographic, histopathological and clinical differences. The main indications and limitations of available cross-sectional imaging techniques are discussed, including ultrasound, computed tomography, magnetic resonance imaging (MRI) and positron emission tomography/computed tomography. A particular emphasis is placed on the review of specific MRI features that may allow distinction between leiomyomas and leiomyosarcomas according to the most recent evidence in the literature. The potential contribution of texture analysis is also discussed. In order to help guide-imaging diagnosis, we provide an MRI-based diagnostic algorithm which takes into account morphological and functional features, both individually and in combination, in an attempt to optimize radiologic differentiation of leiomyomas from leiomyosarcomas.

Uterine carcinosarcoma: a primer for radiologists

OBJECTIVE

To provide a modern overview for radiologists of the unique radiological, pathological, and clinical features of uterine carcinosarcoma (UCS).

RESULTS

UCS is a unique gynecological malignancy that continues to present diagnostic and therapeutic challenges to the field of oncology. The classification and clinical understanding of this malignancy have evolved in recent years, yielding a modern conceptualization of a neoplastic entity that has been well studied but incompletely understood. As UCS causes a significant proportion of deaths secondary to uterine cancer, developing a familiarity with the imaging and clinical features of this entity is critical. In addition to summarizing the modern understanding of this tumor variant, an overview of the common imaging features of UCS will be presented. The role of radiological staging, imaging findings on presentation and follow-up imaging, and modern treatment paradigms will be discussed. Lastly, the current treatment paradigms and surveillance recommendations for UCS will be summarized.

CONCLUSION

Knowledge of the modern understanding of uterine carcinosarcoma, including its relevant imaging and clinical features, is critical for radiologists.

Role of 18F-FDG PET/CT in restaging and follow-up of patients with uterine sarcomas

PURPOSE

Uterine sarcomas are rare tumors with poor prognosis due to the high recurrence rates. The current role of ¹⁸F-FDG PET/CT in the post-therapy surveillance is not established yet.

MATERIALS AND METHODS

Forty-one women with uterine sarcoma underwent 73 ¹⁸F-FDG PET/CT for restaging in suspected recurrence or during follow-up in asymptomatic patients. Histopathology results and/or clinical/imaging follow-up for at least 12 months were considered the reference standard. The diagnostic accuracy and clinical impact of ¹⁸F-FDG PET/CT was calculated.

RESULTS

Thirty-three ¹⁸F-FDG PET/CT were positive, while the remaining 40 studies were negative. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of ¹⁸F-FDG PET/CT were 88%, 98%, 97%, 91% and 93%, respectively. Considering patients with clinical or radiological suspicion of recurrence (n=47) and those during follow-up (n=26), sensitivity, specificity, PPV, NPV and accuracy of ¹⁸F-FDG PET/CT were 89%, 100%, 100%, 86% and 94%, and 80%, 95%, 80%, 95% and 92%, respectively. ¹⁸F-FDG PET/CT had a positive clinical impact in 9/73 (12%) studies and changed the clinical management in 8/41 (20%) patients.

CONCLUSIONS

¹⁸F-FDG PET/CT seems to be an accurate method for detection and localization of local and distant recurrence in patients with uterine sarcoma with good sensitivity and specificity and significant impact on clinical decision making.

Diagnostic Value of 18F-FDG PET/CT and MRI in the Preoperative Evaluation of Uterine Carcinosarcoma

Purpose

This study aimed to compare the diagnostic value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and magnetic resonance imaging (MRI) in the preoperative evaluation of uterine carcinosarcoma.

Methods

Fifty-four women with pathologically confirmed uterine carcinosarcoma who underwent preoperative FDG PET/CT and MRI from June 2006 to November 2016 were included. Pathologic findings from primary tumor lesions, para-aortic and pelvic lymph node (LN) areas, and peritoneal seeding lesions were compared with the FDG PET/CT and MRI findings. The maximum standardized uptake value (SUVmax) of the primary tumor and LN was obtained. The tumor-to-liver ratio (TLR) was calculated by dividing the SUVmax of the primary tumor or LN by the mean SUV of the liver.

Results

For detecting primary tumor lesions (n = 54), the sensitivity and accuracy of FDG PET/CT (53/54) and MRI (53/54) were 98.2%. The sensitivity, specificity, and accuracy of FDG PET/CT versus MRI were as follows: 63.2% (12/19) versus 26.3% (5/19), 100% (35/35) versus 100% (35/35), and 87.0% versus 74.0%, respectively, for pelvic LN areas (p = 0.016); 85.7% (12/14) versus 42.9% (6/14), 90% (36/40) versus 97.5% (39/40), and 88.9% versus 83.3%, respectively, for para-aortic LN areas (p = 0.004); and 59.4% (19/32) versus 50% (16/32), 100% (22/22) versus 100% (22/22), and 75.9% versus 70.4%, respectively, for peritoneal seeding lesions (p = 0.250). For distant metastasis, the sensitivity, specificity, and accuracy of FDG PET/CT were 100 (8/8), 97.8 (45/46), and 98.2%, respectively.

Conclusions

FDG PET/CT showed superior diagnostic accuracy compared to MRI in detecting pelvic and para-aortic LN metastasis in patients with uterine carcinosarcoma. Moreover, FDG PET/CT facilitated the identification of distant metastasis.

Value of 18F-FDG PET/CT imaging in the staging, restaging, monitoring of response to therapy and surveillance of uterine leiomyosarcomas

OBJECTIVE

Leiomyosarcoma (LMS) is the most common subtype of uterine sarcomas. It is a rare and aggressive tumour. The aim of the present study was to assess the performance of fluorine-18-fluorodeoxyglucose (F-FDG) PET/CT imaging in four clinical settings: initial staging, restaging, monitoring of response to therapy and post-therapy surveillance of uterine LMS.

PATIENTS AND METHODS

A bicentric retrospective study was carried out on a group of 21 patients with uterine LMS for whom a total of 52 PET/CT scans were available in initial staging (n=11), restaging (n=11), monitoring of response to therapy (n=17) and post-therapy surveillance (n=13). Clinical (minimum 6 months after PET/CT scan) and/or imaging follow-up and pathology were used as the reference standard.

RESULTS

In the initial staging, the sensitivity, specificity and accuracy of PET imaging were 80, 100 and 91%, respectively. In the restaging and monitoring of response to therapy, all these indices were 100%, whereas they were lower in post-therapy surveillance at 75, 100 and 85%, respectively, because of two false-negative results. False-negative lesions were an infracentimetric lung nodule in the initial staging and a peritoneal nodule that had increased in size between two PET/CT scans in post-therapy surveillance. PET-negative lesions were all identified on the computed tomography (CT) part of the PET/CT; thus, the performances of the exam improved to 100% on taking into account the CT component of the PET/CT.

CONCLUSION

PET/CT imaging has a high diagnostic yield in the initial staging and restaging of uterine LMS, but seems less sensitive in post-therapy surveillance. Evaluation of the CT part improves the sensitivity of the PET scan. Thus, PET/CT imaging should be considered in patients presenting with LMS.

True hypopharyngeal carcinosarcoma: a case report and literature review

Objective

Carcinosarcoma consists of carcinomatous and sarcomatous tissues and is an aggressive malignant tumor. It is rarely reported in the hypopharynx.

Methods

A 72-year-old man presented with dysphagia and dyspnea. Laryngoscopy, computed tomography (CT), and ¹⁸F-fluorodeoxyglucose positron emission tomography/CT (¹⁸F-FDG PET/CT) showed a neoplasm on the left posterior hypopharyngeal wall. The patient underwent bilateral neck dissection and excision of the hypopharyngeal cancer followed by postoperative radiation therapy.

Results

Immunohistochemistry revealed carcinomatous cells with membrane positivity for cytokeratin, glucose transporter-1 (GLUT-1), phosphoinositide-3 kinase (PI3K), hypoxia-inducible factor-1α (HIF-1α), and hexokinase-II as well as sarcomatous cells with membrane positivity for smooth muscle actin, GLUT-1, HIF-1α, and PI3K. Histopathology and immunohistochemistry revealed a true carcinosarcoma of the hypopharynx (pT3N0M0, Stage III).

Conclusions

Thorough immunohistochemistry is required for a correct diagnosis of hypopharyngeal carcinosarcoma. ¹⁸F-FDG PET/CT may help to distinguish hypopharyngeal carcinosarcoma from benign tumors.

Presurgical Identification of Uterine Smooth Muscle Malignancies through the Characteristic FDG Uptake Pattern on PET Scans

The unidentified presence of uterine smooth muscle malignancies poses a tremendous risk in women planning surgery for presumed benign leiomyomas. We sought to investigate whether preoperative FDG PET may be useful to identify leiomyosarcomas (LMS) and smooth muscle tumors of uncertain malignant potential (STUMP). Methods. We investigated patients with rapidly growing uterine masses which were suspected of being malignant on ultrasound or MRI. Among the 21 patients who underwent FDG PET, we identified 7 LMS, 1 STUMP, and 13 leiomyomas. PET-derived parameters and FDG uptake patterns were analyzed retrospectively. Results. The SUV_max values of LMS/STUMP (range: 3.7–11.8) were significantly higher than those observed in leiomyomas (range: 2.0–9.4; P=0.003) despite a significant overlap. The metabolic tumor/necrosis ratio was significantly higher in LMS/STUMP than in leiomyomas (P < 0.001), with no significant intergroup overlaps. All LMS/STUMP revealed a characteristic pattern of FDG uptake, identifying a specific “hollow ball” sign (corresponding to areas of coagulative tumor necrosis). In contrast, this sign was invariably absent in patients with leiomyomas. Conclusion. The characteristic FDG uptake pattern instead of SUV on PET images allows identifying LMS/STUMP in patients with rapidly growing uterine masses, avoiding the deleterious consequences of regular surgery for presumed benign leiomyomas.

Prognostic value of metabolic parameters determined by preoperative ¹⁸F-FDG PET/CT in patients with uterine carcinosarcoma

Objective

To evaluate the prognostic value of metabolic parameters measured by preoperative ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in patients with uterine carcinosarcoma (UCS).

Methods

Data of 55 eligible patients with UCS who underwent preoperative ¹⁸F-FDG PET/CT and surgical staging were analyzed retrospectively. Maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV_2.5), and total lesion glycolysis (TLG_2.5) of the primary tumors were measured using a SUV threshold of 2.5. The optimal cutoff value of each parameter was determined by time-dependent receiver operating characteristic curve, and its impact on progression-free survival and overall survival was evaluated by Cox proportional hazards model.

Results

During a median follow-up period of 29 (range, 1.5–109.4) months, 47.3% (26/55) of the patients experienced disease progression, and the disease-associated mortality rate was 43.6% (24/55). Univariate analysis determined that hazard ratios (HRs) for disease progression for SUV_max (≥8.33), MTV_2.5 (≥63.92 mL), and TLG_2.5 (≥396.16) were 1.930 (95% confidence interval [CI]=0.793–4.701), 3.264 (95% CI=1.466–7.268), and 2.692 (95% CI=1.224–5.924), respectively. And, HRs for death were 1.979 (95% CI=0.774–5.060), 2.764 (95% CI=1.217–6.274), and 2.721 (95% CI=1.198–6.182), respectively. While peritoneal cytology, histology, and tumor diameter were independent prognostic factors in multivariate analysis, MTV and TLG were not.

Conclusion

Though MTV and TLG of primary UCS were not independent predictors compared to surgically obtained data, MTV and TLG of primary UCS may provide useful information on prognosis especially in patients who are not able to undergo surgical staging.

Magnetic Resonance Imaging in Mixed Mullerian Tumour: Report of Two Cases

Malignant Mixed Mullerian Tumours (MMMTs) or carcinosarcomas of uterus are rare aggressive tumours of mesenchymal origin. It is associated with high incidence of lymphatic, pulmonary and peritoneal metastasis. We hereby present two cases of mixed mullerian tumour. Case-1 was a 60-year-old post menopausal woman who had come with complaint of metrorrhagia and a protruding mass in the vagina. Case-2 was of a 54-year-old post-menopausal woman who came with complaints of heavy vaginal bleeding, pelvic pain since two months. For the assessment of these tumours Magnetic Resonance Imaging (MRI) is preferred imaging modality due to excellent tissue contrast to detect the myometrial invasion, local extent and staging. Preoperative differentiation of mullerian tumour with endometrial carcinoma is important as both have different treatment.

FDG PET/CT in Sarcomatoid Carcinoma of the Gallbladder With Chondroid Differentiation

Sarcomatoid carcinoma of the gallbladder, composed of epithelial and sarcomatous components, is a rare malignant tumor with a poor prognosis. A 61-year-old man was admitted because of abdominal distention for 2 weeks. Enhanced CT showed a large gallbladder tumor with central necrosis. The tumor measuring 18 cm in maximum diameter showed intense peripheral FDG uptake with SUVmax of 15.4. The specimen of the resected tumor revealed tubular adenocarcinoma and sarcomatoid tissue with chondroid differentiation. Immunohistochemical staining showed the sarcomatoid tissue was positive for EMA, CD10, and VIM, with proliferation index of 80%. These pathologic findings were consistent with sarcomatoid carcinoma.

Laparoscopic surgery on broken points for uterine sarcoma in the early stage decrease prognosis

Uterine sarcoma, a rare solid tumor in uterus, is difficult to identify in the early stage from some benign uterine tumors, such as uterine fibroids. Hence, uterine sarcoma may be treated in the same way as uterine fibroids; and this may not be found until pathological diagnosis. Consequently, this can lead to tumor's abdominal spread, planting and local invasive growth, resulting in an early uterine sarcoma, an increased relapse rate after surgery and a decreased survival. Therefore, it's important to avoid these unintended and iatrogenic complications through an accurate diagnosis and an appropriate surgical approach. The surgical staging and a complete resection of the tumor are both important for patients' prognosis. In this review, we will discuss the laparoscopic surgery for uterine sarcoma in the early stage and patients' prognosis.

Outcome and Predictive Factors in Uterine Carcinosarcoma Using Postoperative Radiotherapy: A Rare Cancer Network Study

Uterine carcinosarcomas (UCS) are rare tumors. Consensus regarding therapeutic management in non-metastatic disease is lacking. This study reports on outcome and predictive factors when using postoperative radiotherapy. We analyzed a retrospective analysis in 124 women treated between 1987-2007 in the framework of the Rare-Cancer-Network. Median follow-up was 27 months. Postoperative pelvic EBRT was administered in 105 women (85%) and 92 patients (74%) received exclusive or additional vaginal brachytherapy. Five-year overall survival (OS), disease-free survival (DFS), cancer specific survival (CSS) and locoregional control (LRC) were 51.6% (95% CI 35-73%), 53.7% (39-71%), 58.6% (38-74%) and 48% (38-67%). Multivariate analysis showed that external beam radiation therapy (EBRT) >50Gy was an independent prognostic factor for better OS (P=0.03), CSS (P=0.02) and LRC (P=0.01). Relative risks (RR) for better OS (P=0.02), DFS (P=0.04) and LRC (P=0.01) were significantly associated with younger age (≤60 years). Higher brachytherapy (BT)-dose (>9Gy) improved DFS (P=0.04) and LRC (P=0.008). We concluded that UCS has high systemic failure rate. Local relapse was reduced by a relative risk factor of over three in all stages of diseases when using higher doses for EBRT and brachytherapy. Postoperative RT was most effective in UCS stage I/II-diseases.

Comparison of MRI and 18F-FDG PET/CT in the preoperative evaluation of uterine carcinosarcoma

OBJECTIVE

To compare the validities of magnetic resonance imaging (MRI) and (18)F-fluoro-deoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in preoperative evaluation of uterine carcinosarcoma.

METHODS

Pathologic results of primary tumor lesions and paraaortic and pelvic lymph node (LN) areas were compared with the preoperative image findings. Differences in the validity parameters of both images were compared using McNemar test.

RESULTS

For detecting primary tumor lesions (n=56), the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for (18)F-FDG PET/CT versus MRI were 98.1% versus 98.1% (P=1.000), 33.3% versus 100% (P=0.157), 94.6% versus 98.2% (P=0.500), 96.3% versus 100%, and 50% versus 75%, respectively. For paraaortic LN areas, the values were 77.8% versus 51.9% (P=0.016), 90.2% versus 100% (P=0.025), 85.9% versus 83.3% (P=0.774), 80.8% versus 100%, and 88.5% versus 79.7%, respectively. For pelvic LN areas, the values were 61.1% versus 50% (P=0.125), 86.8% versus 89.5% (P=0.727), 78.6% versus 76.8% (P=0.774), 68.8% versus 69.2%, and 82.5% versus 79.1%, respectively. For extrauterine disease, the patient-based values for (18)F-FDG PET/CT were 100%, 78.9%, 85.7%, 69.2%, and 100%, respectively.

CONCLUSION

In patients with uterine carcinosarcoma, (18)F-FDG PET/CT is comparable to MRI in detecting primary uterine lesions. For predicting LN metastases, though (18)F-FDG PET/CT might be insufficient for replacing lymphadenectomy or MRI, it might allow lymphadenectomy to be omitted in poor surgical candidates. For detecting extrauterine metastases, it could also be useful to identify unsuspected disease.

Gynecologic oncologic imaging with PET/CT

FDG-PET/CT has been evaluated in a variety of gynecologic malignancies in a variety of settings and is approved by the Centers for Medicare & Medicaid Services for the initial and subsequent treatment strategies of these malignancies. Cervical cancer is typically very FDG avid, and FDG-PET/CT appears to be most valuable for initial staging, radiation therapy planning, and detection of recurrent disease. For ovarian cancer, the most value of FDG-PET/CT appears to be for detecting recurrent disease in the setting of rising CA-125 level and negative or equivocal anatomical imaging studies. Initial studies evaluating response to therapy are promising and further work in this area is needed. FDG uptake in both nonmalignant and physiological processes in the pelvis can make interpretation of FDG-PET/CT in this region challenging and knowledge of these entities and patterns can avoid misinterpretation. Some of the most common findings relate to the cyclic changes that occur as part of the menstrual cycle in premenopausal women. Mucinous tumors and low-volume or peritoneal carcinomatosis are causes of false-negative results on FDG-PET/CT studies. As new tracers are developed, comparisons with patient outcomes and standards of care (eg, FDG-PET/CT) will be needed.

PET-based radiation therapy planning

In this review, we review the literature on the use of PET in radiation treatment planning, with an emphasis on describing our institutional methodology (where applicable). This discussion is intended to provide other radiation oncologists with methodological details on the use of PET imaging for treatment planning in radiation oncology, or other oncologists with an introduction to the use of PET in planning radiation therapy.

F-18 fluorodeoxyglucose positron emission tomography/computed tomography in a rare case of recurrent malignant mixed mullerian tumor

We report a case of 66-year-old female with previous history of histopathologically proven. Malignant mixed mullerain tumor of the uterus in whom positron emission tomography/computed tomography (CT) done for characterization of soft tissue lesion in pelvis noticed on CT, showed extensive recurrent disease in the pelvis with pulmonary metastases.

Diagnostic performance of fluorine-18-fluorodeoxyglucose positron emission tomography imaging in uterine sarcomas: systematic review and meta-analysis of the literature

OBJECTIVE

We reviewed the medical literature on the application of fluorine-18-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) imaging in the management of uterine sarcomas and presented the results in systematic review and meta-analysis format.

METHODS

Medline, SCOPUS, and ISI Web of Knowledge were searched electronically with "PET AND (Uterine OR Uterus)" as key words. All studies evaluating the accuracy of (18)F-FDG imaging in the staging or restaging of uterine sarcomas were included if enough data could be extracted for calculation of sensitivity and/or specificity.

RESULTS

Eight studies were included in the systematic review. Only 2 studies reported the accuracy of (18)F-FDG PET imaging in the primary staging of uterine sarcoma with low sensitivity for lymph node staging. For restaging (detection of recurrence), all 8 included studies had quantitative data, and the patient-based pooled sensitivity and specificity were 92.1% (95% confidence interval [95% CI], 82.4-97.4) and 96.2% (95% CI, 87-99.5), respectively. On a lesion-based analysis, sensitivity was 86.3% (95% CI, 76.7-92.9), and specificity was 94.4% (95% CI, 72.7-99.9). Device used (PET vs PET/CT), spectrum of studied patients, and histology of the sarcoma seem to be factors influencing the overall accuracy of (18)F-FDG PET imaging.

CONCLUSIONS

(8)Fluorine-18-fluorodeoxyglucose PET and PET/CT seem to be accurate methods for detection and localization of recurrence in patients with uterine sarcoma. Further large multicenter studies are needed to validate our results and to correlate both sarcoma type and spectrum of patients to the diagnostic performance of (18)F-FDG PET imaging in recurrence detection. The studies evaluating the accuracy of (18)F-FDG PET imaging for the primary staging of uterine sarcoma are very limited, and no definite conclusion can be made in this regard.

Differentiation of aggressive and indolent subtypes of uterine sarcoma using maximum standardized uptake value

Objective

The aim of the study was to elucidate the differential metabolic activities in aggressive and indolent subtypes of uterine sarcomas, which may aid in managing these heterogeneous tumours.

Methods

We retrospectively analysed the PET/computed tomography scans of consecutive patients (N=18) diagnosed with uterine sarcoma at our unit. The patients were divided into indolent (N=4) and aggressive (N=14) tumour groups, and the maximum standardized uptake values (SUV_max) of all lesions (n=134) were measured. The SUV_max of the lesions were compared between the two tumour groups using the Mann–Whitney U-test. We calculated the optimal cutoff value as determined by receiver operating characteristic analysis. A P-value less than 0.05 was considered statistically significant.

Results

The mean SUV_max of aggressive (n=104) and indolent tumours (n=30) were significantly different (8.0±7.3 vs. 1.9±0.9 respectively; P<0.001). A cutoff of SUV_max greater than 4.0 was able to exclude indolent tumours, with 100% specificity and positive predictive value (sensitivity 72%, negative predictive value 50% and accuracy 78%; area under the curve 97%). By applying this same cutoff value on the most metabolic active lesion in each patient, we were able to correctly classify all but one patient into either the aggressive or indolent tumour group with 100% specificity and positive predictive value (sensitivity 93%, negative predictive value 80% and accuracy 94%).

Conclusion

Aggressive and indolent uterine sarcoma subtypes have differential metabolic activities that can be used to classify them and this can aid in patient management for preoperative surgical planning and treatment stratification.

18F-FLT PET performs better than 18F-FDG PET in differentiating malignant uterine corpus tumors from benign leiomyoma

PURPOSE

The aim of this study is to test the hypothesis that positron emission tomography (PET) with 3'-deoxy-3'-[(18)F]-fluorothymidine ((18)F-FLT) can differentiate malignancy from benign leiomyoma better than PET with 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG), and to evaluate whether (18)F-FLT and (18)F-FDG uptake correlate with immunohistochemical index of cell proliferation.

METHODS

The protocol of this prospective study was approved by the institutional ethics committee, and all patients gave written informed consent. Fifteen patients (aged 26-65 years, median 44 years) with uterine corpus tumor which has the possibility of being leiomyosarcoma underwent (18)F-FLT and (18)F-FDG PET scans. Maximum standard uptake value (SUV(max)) of PET scans and Ki-67 labeling index of surgical specimens were evaluated. Mann-Whitney's U test was used for comparing uptakes between benign and malignant, and linear regression analysis was used for evaluating the correlation between Ki-67 labeling index and SUV(max).

RESULTS

Five cases were diagnosed as malignant (leiomyosarcoma for 3 cases, and carcinoma for 2 cases), and the others were benign leiomyoma. Sensitivity and negative predictive value of both tracers for detecting malignancy was 100%. Specificity, positive predictive value and accuracy of (18)F-FLT PET were higher than those of (18)F-FDG PET. Difference in SUV(max) between malignant and benign was significant for (18)F-FLT PET (P < 0.01), but not for (18)F-FDG PET. While all the malignant cases showed positive uptake in both tracers, a case of leiomyosarcoma with huge necrosis showed relatively low uptake. Uptake of (18)F-FLT showed better correlation with Ki-67 labeling index compared with (18)F-FDG (R(2) = 0.91 vs. R(2) = 0.26).

CONCLUSION

Negative findings on additional (18)F-FDG or (18)F-FLT PET may rule out the possibility of malignancy for the patients with suspected leiomyosarcoma diagnosed by conventional methods. (18)F-FLT PET is superior to (18)F-FDG PET in differentiating malignant from benign leiomyoma. Moreover, (18)F-FLT uptake correlated well with the immunohistochemical index of cell proliferation.

Role of FDG PET-CT in detecting recurrence in patients with uterine sarcoma: comparison with conventional imaging

PURPOSE

The purpose of the present study was to evaluate the role of 18F-fluorodeoxyglucose (FDG) PET-CT in detecting recurrent disease in posttherapy patients of uterine sarcoma and compare the same with conventional imaging (CI).

METHODS

A total of 15 FDG PET-CT studies were acquired in 12 posttherapy uterine sarcoma patients. The images were evaluated by two experienced nuclear medicine physicians in consensus. Clinical/imaging follow-up (minimum 6 months) and histopathology were taken as the reference standard. All the patients had also undergone CI (CT or MRI or ultrasonography) of the chest, abdomen, and pelvis. The diagnostic accuracy of FDG PET-CT was calculated and compared with that of CI.

RESULTS

The median age of the patients was 51.5 years (interquartile range: 47.5-53). Histopathology was leiomyosarcoma in six, carcinosarcoma in five, and endometrial stromal sarcoma in one patient. Six FDG PET-CT studies were carried out for suspected recurrence and nine for posttherapy surveillance. Six FDG PET-CTs were positive and nine were negative for recurrence. The sensitivity, specificity, and accuracy of FDG PET-CT were 85.7, 100, and 93.3%, respectively, on per study-based analysis, and 80, 100, and 83.3% on per lesion-based analysis. PET-CT showed higher sensitivity and specificity compared with CI for both study-based and lesion-based analysis. However, no significant difference was found between FDG PET-CT and CI either in the study-based or in the lesion-based analysis (P not significant).

CONCLUSION

FDG PET-CT is a highly sensitive and specific modality for detecting recurrence in posttherapy patients with uterine sarcoma. However, it provides no significant advantage over CI for this purpose.

[FDG-PET and endometrial cancer]

FDG-PET is widely used for the diagnosis, the staging and the search for recurrence of many tumors. However, there are currently no recommendations for its use in endometrial cancer. This article is an update of the literature data to enable everyone to form an opinion on the subject. Future prospects are considered.

Uterine carcinosarcomas (malignant mixed müllerian tumours): a review with special emphasis on the controversies in management

Uterine carcinosarcomas (MMMT-malignant mixed Müllerian tumours) are highly aggressive, rare, biphasic tumours composed of epithelial and mesenchymal elements believed to arise from a monoclonal origin. While hysterectomy with bilateral salpingo-oophorectomy remains the mainstay treatment, high rates of recurrence and metastases suggest a need for lymphadenectomy and postoperative adjuvant treatment. There are no established consensus guidelines for therapeutic patient management. Though well recognized that it improves locoregional control, the role of radiation in improving overall survival outcomes remains undecided. Although various combinations of chemotherapy have been explored, an optimal therapeutic modality is yet to be determined. As overall survival rates have not improved in thirty years, it is suggested that targeted chemotherapy and/or a multimodality approach may yield better outcomes. This paper provides a summary of the aetiopathogenesis of carcinosarcomas (MMMT) limited to the uterus with special emphasis on the controversies in the management of these patients.

Bilateral Tubo-Ovarian Abscess Mimics Ovarian Cancer on MRI and (18)F-FDG PET/CT

A 20-year-old woman, who presented with a several-week history of abdominal pain, was referred for magnetic resonance imaging (MRI) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after an ultrasound showed complex cystic masses arising from both ovaries. The MRI and (18)F-FDG PET/CT imaging characteristics of the ovarian masses were strongly suspicious for malignancy, and the masses were surgically removed. Histopathological evaluation revealed a bilateral tubo-ovarian abscess, with no evidence of malignancy. This case highlights a potentially serious pitfall in the evaluation of suspicious pelvic masses by (18)F-FDG PET/CT, whereby a complex bilateral tubo-ovarian abscess may mimic the PET/CT imaging characteristics of an ovarian or pelvic malignancy.

Clinical presentation and diagnosis of uterine sarcoma, including imaging

Uterine sarcomas are uncommon tumours from mesenchymal elements. They are thought to arise primarily from endometrial stroma and uterine muscle, respectively. When endometrial stroma undergoes malignant transformation, it might be accompanied by a malignant epithelial component. Thus, malignant mesenchymal uterine tumours comprise leiomyosarcoma, endometrial stromal sarcoma, undifferentiated uterine sarcoma and carcinosarcoma. In this chapter, we discusses preoperative presentation, diagnosis and current progress in different imaging modalities, including ultrasonography, computed tomography, magnetic resonance image and positron emission tomography scan. We summarise advances in new technology, which might improve preoperative detection and enhance referral to gynaecologic oncologists for optimal staging surgery and treatment.

Spectrum of FDG PET/CT findings of uterine tumors

OBJECTIVE

The purpose of this article is to review FDG PET/CT and MRI findings in a variety of benign and malignant tumors of the uterus and to become familiar with the wide variety of FDG PET/CT findings of this entity.

CONCLUSION

Benign uterine tumors generally have mild FDG uptake, and leiomyoma rarely shows high uptake. Uterine malignant tumors generally have intense FDG uptake, whereas malignant uterine tumors that are small or that have low cellular density often show minimal uptake.

PET/CT Imaging in Gynecologic Malignancies Other than Ovarian and Cervical Cancer

Fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is an imaging modality used for staging, assessing response to therapy, and diagnosis of recurrent cervical and ovarian cancer. The potential role of FDG-PET/CT in other gynecologic malignancies such as endometrial cancer, uterine sarcomas, vaginal, and vulvar cancer has not been fully explored.