Metastatic choriocarcinoma with tumor thrombus in the right atrium and pulmonary vessels: diagnosis and therapy monitoring with F-18 flurodeoxyglucose PET/CT

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.

FDG PET/CT appearance of tumor thrombus of ovarian vessels masquerading as retroperitoneal fibrosis

A 23-year-old woman with recurrent uterine endometrial stromal sarcoma underwent FDG PET/CT, which showed pelvic recurrence and multiple pulmonary metastases. In addition, increased activity in a vertical soft tissue mass along the left ureter was noted, which appears similar to retroperitoneal fibrosis on PET/CT images. However, pathological examination demonstrated that the elevated FDG activity in this mass was a result of tumor thrombus from endometrial stromal sarcoma in the left ovarian arteries and veins.

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.