The role of 18F-fluorodeoxyglucose positron emission tomography in gestational trophoblastic tumours: a pilot study

Diagnostic Challenges in Invasive Mole With 18F-FDG PET/CT

ABSTRACT

A 34-year-old woman underwent 18F-FDG PET/CT scan following a diagnosis of an invasive mole. Although CT indicated multiple lung metastases, FDG uptakes were not evident. In contrast, FDG uptakes were observed in the pelvic lesion including the left ovary, suggestive of ovarian metastasis. MRI disclosed a ring-shaped enhancement typical of a corpus luteum. This corpus luteum was supposed to be maintained by the elevated human chorionic gonadotropin excreted from the invasive mole. This case underlines the importance of careful interpretation of 18F-FDG PET/CT in the evaluation of invasive moles, highlighting potential false positive in corpus luteum.

FDG PET/CT Findings of Primary Pulmonary Choriocarcinoma in a Postmenopausal Woman

ABSTRACT

Choriocarcinomas usually occur in the genital tracts of reproductive-age women after a gestational event. Primary pulmonary choriocarcinoma is very rare. We describe FDG PET/CT findings of primary pulmonary choriocarcinoma with multiple intrapulmonary metastases in a postmenopausal woman with elevated serum beta human chorionic gonadotropin level. On FDG PET/CT, the large primary lung tumor showed intense FDG uptake (SUV max , 46), and the small intrapulmonary metastases showed variable FDG uptake (SUV max , 27). Primary pulmonary choriocarcinoma should be included in the differential diagnosis of FDG-avid pulmonary lesions with elevated serum beta human chorionic gonadotropin levels, including metastatic choriocarcinoma and lung cancer.

A poor prognostic male choriocarcinoma with multiple systemic metastases: a case report and the literature review

Background

Non-gestational choriocarcinoma, also known as primary choriocarcinoma, is extremely rare in men, manifesting with specific signs such as breast feminization, testicular atrophy, and loss of libido. The presentation typically includes elevated serum β-hCG levels, widespread metastatic disease, and a rapid progression of the condition.

Case report

We present a rare case of a 41-year-old man diagnosed with choriocarcinoma, exhibiting a unique combination of multiple metastases, including lung, brain, bone, and retroperitoneal lymph node metastases, as confirmed by 18F-FDG PET/CT imaging. The patient was treated with aggressive chemotherapy and pembrolizumab, and the prognosis remained poor. The patient's overall survival was a mere 5 months following diagnosis.

Conclusion

Non-gestational choriocarcinoma represents a rare entity in clinical practice and should be considered in young men presenting with gynaecomastia and elevated β-hCG levels alongside normal gonads. Thus, we advocate for a more comprehensive inquiry into medical history and a systematic examination. The 18F-FDG PET/CT examination not only visually delineates the lesion's location and extent but also serves as a cornerstone for clinical tumor staging, providing valuable support for treatment monitoring and subsequent follow-up.

18F-FDG PET/CT May Predict Tumor Type and Risk Score in Gestational Trophoblastic Disease

PURPOSE

The aim of this study was to investigate the role of 18F-FDG PET/CT in predicting pathological prognostic factors, including tumor type and International Federation of Gynecology and Obstetrics (FIGO) score, in gestational trophoblastic disease (GTD).

METHODS

Retrospective monocentric study including 24 consecutive patients who underwent to 18F-FDG PET/CT from May 2005 to March 2021 for GTD staging purpose. The following semiquantitative PET parameters were measured from the primary tumor and used for the analysis: maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV) and total lesion glycolisis (TLG). Statistical analysis included Spearman correlation coefficient to evaluate the correlations between imaging parameters and tumor type (nonmolar trophoblastic vs postmolar trophoblastic tumors) and risk groups (high vs low, defined according to the FIGO score), whereas area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to assess the predictive value of the PET parameters. Mann-Whitney U test was used to further describe the parameter's potential in differentiating the populations.

RESULTS

SUVmax and SUVmean resulted fair (AUC, 0.783; 95% confidence interval [CI], 0.56-0.95) and good (AUC, 0.811; 95% CI, 0.59-0.97) predictors of tumor type, respectively, showing a low (ρ = 0.489, adjusted P = 0.030) and moderate (ρ = 0.538, adjusted P = 0.027) correlation. According to FIGO score, TLG was instead a fair predictor (AUC, 0.770; 95% CI, 0.50-0.99) for patient risk stratification.

CONCLUSIONS

18F-FDG PET parameters have a role in predicting GTD pathological prognostic factors, with SUVmax and SUVmean being predictive for tumor type and TLG for risk stratification.

Clinical presentation and diagnosis of Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD) is a heterogeneous group of pregnancy-related disorders characterized by abnormal proliferation of trophoblastic tissue. It encompasses the premalignant partial and complete hydatidiform mole but also the malignant invasive mole, choriocarcinoma, placental-site trophoblastic tumor, and epithelioid trophoblastic tumor. The clinical presentation changed to earlier detection after the introduction of first trimester ultrasounds. Patients are often asymptomatic, but vaginal bleeding continues to be the most common presenting symptom. Other symptoms can develop in the case of metastatic disease. Ultrasound, serum human chorionic gonadotrophin, and sometimes additional imaging such as CT, MRI, or PET can confirm the diagnosis and stage of disease. Familiarity with the pathogenesis, classification, imaging features, and treatment of GTD facilitates diagnosis and appropriate management.

ACR Appropriateness Criteria® Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD), a rare complication of pregnancy, includes both benign and malignant forms, the latter collectively referred to as gestational trophoblastic neoplasia (GTN). When metastatic, the lungs are the most common site of initial spread. Beta-human chorionic gonadotropin, elaborated to some extent by all forms of GTD, is useful in facilitating disease detection, diagnosis, monitoring treatment response, and follow-up. Imaging evaluation depends on whether GTD manifests in one of its benign forms or whether it has progressed to GTN. Transabdominal and transvaginal ultrasound with duplex Doppler evaluation of the pelvis are usually appropriate diagnostic procedures in either of these circumstances, and in posttreatment surveillance. The appropriateness of more extensive imaging remains dependent on a diagnosis of GTN and on other factors. The use of imaging to assess complications, typically hemorrhagic, should be guided by the location of clinical signs and symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A Review on the Pathogenesis and Clinical Management of Placental Site Trophoblastic Tumors

Placental site trophoblastic tumor (PSTT) is a rare type of gestational trophoblastic disease originating from the intermediate trophoblast. Compared with hydatidiform mole, invasive hydatidiform mole and choriocarcinoma, the diagnosis of PSTT is more complicated and lacks specific and sensitive tumor markers. Most PSTT patients demonstrate malignant potential, and the primary treatment of PSTT is hysterectomy. However, metastasis occasionally occurs and even causes death in a small number of PSTT patients. Most PSTT patients are young women hence fertility preservation is an important consideration. The major obstacle for PSTT patient prognosis is chemotherapy resistance. However, the current understanding of the pathogenesis of PSTT and clinical treatment remains elusive. In this review, we summarized the research progress of PSTT in recent years from three aspects: mechanism, clinical presentation, and treatment and prognosis. Well-conducted multi-center studies with sufficient sample sizes are of great importance to better examine the pathological progress and evaluate the prognosis of PSTT patients, so as to develop prevention and early detection programs, as well as novel treatment strategies, and finally improve prognosis for PSTT patients.

18F-FDG PET/CT Demonstrating Chorioadenoma Destruens After Evacuation of Complete Hydatidiform Mole

Gestational trophoblastic neoplasias (GTNs) are a group of pregnancy-related neoplasms, which include chorioadenoma destruens (invasive mole), placental site trophoblastic tumor, and choriocarcinoma. Although the role of F-FDG PET/CT is still undefined in GTN, in selected cases, it can have significant impact on patient management. Here, we present the case of a 29-year-old woman with hydatidiform mole suggestive of GTN 3 months after evacuation. F-FDG PET/CT demonstrated chorioadenoma destruens (invasive mole) and ruled out metastasis in this case.

Historical, morphological and clinical overview of placental site trophoblastic tumors: from bench to bedside

INTRODUCTION

Placental site trophoblastic tumor (PSTT) is a form of gestational trophoblastic disease that originates from the implantation of an intermediate trophoblast. It was described for the first time by Von F. Marchand in 1895 as belonging to chorioepithelioma sui generis, a pathological condition with many variations and a progressive degree of malignancy.

METHODS

We have conducted a literature review in MEDLINE about epidemiology, etiopathogenesis and clinical features of PSTT. Moreover, a case that occurred in our institution was reported.

RESULTS

Our research has highlighted that existing published data about PSTT are not uniform. The number of cases described in the literature has updated and the clinical features of selected "case series" of patients diagnosed with PSTT were showed. The etiopathogenesis was discussed. It was noted that current prognostic factors still allow important information regarding PSTT to be obtained, albeit fragmentary.

CONCLUSIONS

The lack of uniformity in data collection seen so far has limited full knowledge of PSTT. For this reason, we suggest a model (PSTT model) that collects and unifies PSTT evidence as this would be useful to identify worldwide precise prognostic factors, which are still lacking. When PSTT is diagnosed, the proper procedure seems to be total hysterectomy, with sampling of pelvic lymph nodes and ovarian conservation. For advanced-stage diseases, (stage III and IV) a combination of surgery and polychemotherapy is suggested.

Gestational trophoblastic disease: a multimodality imaging approach with impact on diagnosis and management

Gestational trophoblastic disease is a condition of uncertain etiology, comprised of hydatiform mole (complete and partial), invasive mole, choriocarcinoma, and placental site trophoblastic tumor. It arises from abnormal proliferation of trophoblastic tissue. Early diagnosis of gestational trophoblastic disease and its potential complications is important for timely and successful management of the condition with preservation of fertility. Initial diagnosis is based on a multimodality approach: encompassing clinical features, serial quantitative β-hCG titers, and pelvic ultrasonography. Pelvic magnetic resonance imaging (MRI) is sometimes used as a problem-solving tool to assess the depth of myometrial invasion and extrauterine disease spread in equivocal and complicated cases. Chest radiography, body computed tomography (CT), and brain MRI have been recommended as investigative tools for overall disease staging. Angiography has a role in management of disease complications and metastases. Efficacy of PET (positron emission tomography) and PET/CT in the evaluation of recurrent or metastatic disease has not been adequately investigated yet. This paper discusses the imaging features of gestational trophoblastic disease on various imaging modalities and the role of different imaging techniques in the diagnosis and management of this entity.

Role of 18F-FDG PET in the management of gestational trophoblastic neoplasia

PURPOSE

Gestational trophoblastic neoplasia (GTN) is a rare and aggressive tumour that is usually sensitive to chemotherapy. The usefulness of conventional imaging modalities in evaluating treatment response is limited, mainly due to the difficulty in differentiating between residual tumour tissue and necrosis. The aim of the present study was to evaluate the role of FDG PET or PET/CT in primary staging and in monitoring treatment efficacy. The effect of FDG PET and combined PET/CT on the management of patients with GTN was also evaluated comparing the differences between standard treatments based on conventional imaging and alternative treatments based on PET.

METHODS

This retrospective study included 41 patients with GTN referred to San Raffaele Hospital between 2002 and 2010. All patients were studied by either PET or PET/CT in addition to conventional imaging. Of the 41 patients, 38 were evaluated for primary staging of GTN and 3 patients for chemotherapy resistance after first-line chemotherapy performed in other Institutions. To validate the PET data, PET and PET/CT findings were compared with those from conventional imaging, including transvaginal ultrasonography (TV-US) in those with uterine disease, CT and chest plain radiography in those with lung disease and whole-body CT in those with systemic metastases. Conventional imaging was considered positive for the presence of uterine disease and/or metastases when abnormal findings relating to GTN were reported. PET and PET/CT were considered concordant with conventional imaging when metabolic active disease was detected at the sites corresponding to the pathological findings on conventional imaging. In addition, in 12 of the 41 patients showing extrauterine disease, FDG PET/CT was repeated to monitor treatment efficacy, in 8 after normalization of beta human chorionic gonadotropin (βHCG) and in 4 with βHCG resistance. In some patients, PET or PET/CT findings led to an alternative nonconventional treatment, and this was considered a change in patient management for the study analysis.

RESULTS

When compared to TV-US, chest radiography and CT for staging, PET showed a concordance in 91 %, 84 % and 81 % of patients, respectively. In 8 of the 41 patients with extrauterine disease during staging, PET/CT showed a complete response to therapy after βHCG normalization. PET and PET/CT identified the sites of persistent disease in all seven high-risk patients with βHCG resistance, of whom four underwent second-line chemotherapy, two surgical removal of resistant disease instead of additional chemotherapy, and one surgical removal of resistant disease and second-line chemotherapy with subsequent negative βHCG.

CONCLUSION

In staging, PET cannot replace conventional imaging and does not show any information in addition to that shown by conventional imaging. The additional value of PET/CT in GTN with respect to conventional imaging is found in patients with high-risk disease. PET can identify the sites of primary and/or metastatic disease in patients with persistent high levels of βHCG after first-line chemotherapy and may be of additional value in patient management for guiding alternative treatment.

Primary epithelioid trophoblastic tumor with a synchronous breast carcinoma detected only with FDG-PET/CT Scan

Epithelioid trophoblastic tumor is a recently described, rare and distinctive type of gestational trophoblastic tumor. We report the case of a 31-year old patient who had a full-term pregnancy 18 months before presentation. She had a right axillary lymph node metastasis and was referred for FDG-PET/CT scan for evaluation of distant metastasis and to detect primary malignancy. The axillary lymph node biopsy revealed metastatic breast carcinoma. FDG-PET/CT revealed increased uptake of right axillary lymph node, soft tissue density lesion with a diameter of 24 mm on left cervical region with increased FDG uptake, increased uptake on cervical region and left inguinal lymph node with increased uptake. Pelvic MRI imaging and ultrasonography were negative for malignancy in cervical region. Biopsy of the lesion was consistent with epithelioid trophoblastic tumor in cervical region. Gestational trophoblastic tumor was not suspected because she had no signs such as abnormal vaginal bleeding. FDG-PET/CT demonstrated the primary lesion in cervical region. We report a rare case of primary epithelioid trophoblastic tumor detected only with FDG-PET/CT scan which synchronized with breast carcinoma.

Placental-site trophoblastic tumor with PET scan-detected surgically treated lung metastasis

Metastatic placental-site trophoblastic tumor (PSTT) continues to be a diagnostic and management dilemma due to its relative resistance to chemotherapy and the difficulties in diagnosing such a rare tumor. We describe a 35-year-old woman with PSTT presenting with irregular bleeding and a mass in the lung. Dilation and curettage provided the diagnosis of PSTT by frozen section of the specimen. Subsequently, a total abdominal hysterectomy was performed and the patient received three cycles of EMA-CO (etoposide, methotrexate, actinomycin D, cyclophosphamide, and vincristine) Positron emission tomography (PET) scan confirmed a persistent lung nodule that was treated with wedge resection. She is currently in clinical remission. Surgery may have a role in salvaging a patient with persistent PET-positive disease after chemotherapy.

Detection of primary choriocarcinoma in the mediastinum by F-18 FDG positron emission tomography

A 31-year-old woman with a history of infection with human papilloma virus was found to have an elevated human chorionic gonadotropin level (beta-HCG) of more than 9000 IU/L in January 2006. The patient reported an irregular menstrual cycle. Extensive clinical work-up including gynecologic examinations with laparoscopy, hysteroscopy, and curettage were performed but no pathologic explanation of this elevated beta-HCG could be found. In the initial computed tomography (CT) of the abdomen and the thorax, a tumor could not be detected. Based on a clinical decision, chemotherapy with methotrexate in a dose of 1 mg/kg body weight was started. Four months after beginning of the chemotherapy the beta-HCG level dropped to 3048 IU/L. At this time a first F-18 FDG PET was performed and the findings were negative. After completion of 7 cycles of chemotherapy the beta-HCG level rose again. In a second F-18 FDG PET in August 2006 focal, intense and pathologic F-18 FDG accumulation with a SUV max. of 5.4 was seen in the mediastinum in the region of the thymus. At this time the beta-HCG level was 7000 IU/L. In a subsequent CT of the chest a retrosternal mass of 4 x 1.7 cm was detected with contrast enhancement. Resection of the tumor and thymus gland demonstrated a choriocarcinoma in part adjacent to the thymus and in part in the thymus. Postoperative beta-HCG levels dropped to 105 IU/L.

Positron emission tomography imaging for gynecologic malignancy

PURPOSE OF REVIEW

The utility of positron emission tomography (PET) in gynecologic malignancy has increased rapidly in recent years. This review examines publications in this area.

RECENT FINDINGS

PET scans are mostly performed using 18-fluorodeoxyglucose (FDG-PET). It is valuable in primary staging of untreated advanced cervical cancer, for posttreatment unexplained tumor marker elevation and restaging of potentially curable recurrent cervical cancer. Its value in early-stage cervical cancer is limited. In ovarian cancer, sequential imaging predicts response to neoadjuvant chemotherapy and survival. It also provides benefits when increases in serum CA 125 or computed tomography/magnetic resonance imaging defined recurrence is noted but biopsy deemed infeasible. A few studies have shown that FDG-PET may facilitate optimal management of endometrial cancer, especially for posttherapy surveillance and after salvage therapy. FDG-PET is potentially useful in selected gestational trophoblastic neoplasia by monitoring response and localizing viable tumors after chemotherapy. Scanty studies have been reported in vulvar and vaginal cancer. The methodology and prospects of using integrated PET/computed tomography in the management of gynecological cancer are discussed. Other PET compounds are briefly introduced.

SUMMARY

The role of PET or PET/computed tomography has evolved from a diagnostic tool into a potential indicator of response to treatment and prognosis. Evaluating this tool by clinical impact is an attractive end point.