Clinical characteristics and prognostic factors of male yolk sac tumor: a Surveillance, Epidemiology, and End Results program study

Variations in germ cell tumor histology by age and implications for cancer-specific survival among pediatric and adult males: A population-based study

PURPOSE

Few studies have quantified differences in histology and implications for survival between male children and adults with germ cell tumors (GCT). We evaluated these differences and associations with cancer-specific survival (CSS) using Surveillance, Epidemiology, and End Results (SEER) cancer registries.

METHODS

SEER (1988-2016) was used to identify male patients 0 to 40 years of age diagnosed with seminoma and nonseminomatous GCT (NSGCT). Demographic and tumor characteristics were tabulated with histology distributions compared by age group (0-4, 12-18, 19-40 years old). CSS was evaluated in multivariable Cox proportional hazards regression models.

RESULTS

Among 27,204 patients identified, 1,538 (5.7%) were pediatric (0-18 years). Seminoma (54.3%) predominated in adult patients (ages 19-40). Among 0 to 4 years-old, yolk sac tumor (71.2%) and teratoma (21.5%) were most common. Mixed GCT (52.7%) was most prevalent among 12 to 18 years-old with seminoma, embryonal, and teratoma occurring in 12 to 15% each. Relative to pediatric patients, adult patients had similar CSS for seminoma but worse CSS for NSGCT on Kaplan-Meier curves with 9 years mean follow-up. Choriocarcinoma and yolk sac tumors carried the worst prognosis relative to seminoma for both children (HR 5.7 and HR 11.1, respectively, both P < 0.01) and adults (HR 4.6 and HR 4.6, respectively, both P < 0.01) adjusted for stage.

CONCLUSION

Histology of GCTs vary by age with yolk sac tumors and teratoma predominating for male patients 0 to 4 years, mixed GCT for 12 to 18 years, and seminoma for 19 to 40 years. Pediatric patients with NSGCT had higher CSS than their adult counterparts. Mixed GCT represented an increasing proportion of GCT over the study period. Age, stage, and histology impact CSS in both pediatric and adult populations.

Clinical characteristics and prognostic models of gonadal and extra-gonadal yolk sac tumors: a population-based analysis in children and adolescents

PURPOSE

Yolk sac tumors (YST) are a rare and aggressive germ cell tumor. We aimed to conduct a population-based cohort study and develop a nomogram to predict overall survival (OS) in pediatric patients with YST.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify all pediatric patients with YST diagnosed between 2000 and 2018. The log-rank test was used to compare survival curves. To examine the impact of each factor on overall survival, a multivariate Cox proportional hazards model was created. Based on the results of the Cox regression model, a nomogram was constructed.

RESULTS

A total of 520 YST patients were identified. Overall survival rates for all patients were 92.2% at 3-year and 90.3% at 5-year, respectively. The outcome of Cox proportional hazard regression revealed that age, gender, primary sites, and treatment regimens were important independent predictors in this model. Based on the Cox regression model, we created a nomogram for predicting OS in pediatric YST patients. The chance of death increased with age in patients. Furthermore, patients with extra-gonadal YST have a lower survival rate than those with gonadal YST.

CONCLUSIONS

Our study revealed that age, gender, and primary site were found to be the most important predictors of the overall survival of pediatric YST, providing crucial epidemiological information for clinical management.

Primary mediastinal yolk sac tumor: A case report and literature review

Key Clinical Message

There are limited published cases of primary mediastinal yolk sac tumor (PMYST), with no consensus on the best treatment alternative. By far, the surgery oriented comprehensive therapies are the main treatment methods. The surgical strategy should be individualized and aimed at radical resection, considering all the possibilities, including the use of cardiopulmonary bypass and prosthetic materials.

Abstract

A 15-year-old boy was diagnosed as PMYST. The tumor, with a size about 13 × 12 × 8 cm, was located in the right upper mediastinum, closely adhering to ascending aorta, superior vena cava, right atrium, and the right hilum. After 6 cycles chemotherapy of bleomycin, etoposide, and cisplatin (BEP), no significant change was found in the size of tumor. Subsequently, an extended tumor excision including partial resection of the right lung, the pericardium, the diaphragm and the right phrenic nerve, was performed successfully with cardiopulmonary bypass on standby. During 6 months of follow-up, there was no tumor recurrence. Meanwhile, in PubMed, we searched the English case reports and case series of PMYST during the past decade. A total of 73 articles were retrieved, in which 22 articles on the therapy and prognosis of PMYST were extracted and reviewed, included 16 case reports and 6 case series with a total of 52 patients. Due to the rarity of PMYST, it is difficult to provide a specific treatment regimen. The surgery-oriented comprehensive therapies are still the main treatment methods. The surgical strategy should be individualized and aim at radical resection, considering all the possibilities, including the use of cardiopulmonary bypass and prosthetic materials.

Clinical features and prognostic factors in patients diagnosed with lymphovascular invasion of testicular germ-cell tumors: Analysis based on the SEER database

Background

Lymphovascular invasion (LVI) is a high-risk factor for testicular germ-cell tumors (TGCT), but a prognostic model for TGCT-LVI patients is lacking. This study aimed to develop a nomogram for predicting the overall survival (OS) of TGCT-LVI patients.

Methods

A complete cohort of 3288 eligible TGCG-LVI patients (training cohort, 2300 cases; validation cohort, 988 cases) were obtained from the Surveillance, Epidemiology, and End Results database. Variables screened by multivariate Cox regression analysis were used to construct a nomogram, which was subsequently evaluated using the consistency index (C-index), time-dependent receiver operating characteristic curve (ROC), and calibration plots. The advantages and disadvantages of the American Joint Committee on Cancer (AJCC) staging system and the nomogram were assessed by integrated discrimination improvement (IDI) and net reclassification improvement (NRI). Decision-analysis curve (DCA) was used to measure the net clinical benefit of the nomogram versus the AJCC staging system. Finally, Kaplan-Meier curves were used to evaluate the ability to identify different risk groups between the traditional AJCC staging system and the new risk-stratification system built on the nomogram.

Results

Nine variables were screened by multivariate Cox regression analysis to construct the nomogram. The C-index (training cohort, 0.821; validation cohort, 0.819) and time-dependent ROC of 3-, 5-, and 9-year OS between the two cohorts suggested that the nomogram had good discriminatory ability. Calibration curves showed good consistency of the nomogram. The NRI values of 3-, 5-, and 9-year OS were 0.308, 0.274, and 0.295, respectively, and the corresponding values for the validation cohort were 0.093, 0.093, and 0.099, respectively (P<0.01). Additionally, the nomogram had more net clinical benefit as shown by the DCA curves, and the new risk-stratification system provided better differentiation than the AJCC staging system.

Conclusions

A prognostic nomogram and new risk-stratification system were developed and validated to assist clinicians in assessing TGCT-LVI patients.

Extragonadal Germ Cell Tumors of the Mediastinum and Retroperitoneum: A Surveillance, Epidemiology, and End Results-based Study

OBJECTIVES

Extragonadal germ cell tumors (EGCT) are a rare entity, most of them being located in the mediastinum and retroperitoneum. Information on these tumors is scarce, requiring carrying out large population-based studies to better understand these diseases. We aimed to determine the clinical features and prognosis of patients with EGCT of the mediastinum and retroperitoneum.

MATERIALS AND METHODS

Demographic and clinicopathological features of patients diagnosed with EGCT of the mediastinum and retroperitoneum from 1975 to 2016 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database.

RESULTS

A total of 1674 patients were included, 1297 (77.5%) of mediastinal origin and 377 (22.5%) of retroperitoneum. Nonseminomatous tumors (56.3%) were slightly more frequent than seminomas (43.7%) with similar distribution between mediastinum and retroperitoneum. After a median follow-up of 137 months, the median overall survival was 263 months (95% CI, 220-296) whereas the median cause-specific survival (CSS) has still not been reached. The 10-year overall survival and CSS were 57.4% (95% CI, 55-59.7) and 63% (95% CI, 60.6-65.2) respectively. Multivariate analysis showed that older age, mediastinal location, nonseminomatous histology, and distant disease at diagnosis were independent prognostic factors correlated with a worse prognosis. Patients with mediastinal choriocarcinoma and embryonal carcinoma have the worst prognosis, both with a median CSS of only 12 months.

CONCLUSIONS

Despite a decreasing incidence observed in recent decades, EGCT continues to represent a challenge for oncologists. The prognosis of choriocarcinoma and embryonal carcinoma of the mediastinum remains poor and treatment strategies need to be improved urgently.

Develop and validate nomogram to predict cancer-specific survival for patients with testicular yolk sac tumors

Purpose

Testicular yolk sac tumor (TYST) is a rare malignant germ cell tumor that mainly occurs in young men. Due to the low incidence of yolk sac tumors, there is a lack of prospective cohort studies with large samples. We aimed to develop a nomogram to predict cancer-specific survival (CSS) in patients with TYST.

Materials and methods

Patient information was downloaded from the Surveillance, Epidemiology and End Results (SEER) database. We enrolled all patients with TYST from 2000 to 2018, and all patients were randomly divided into a training set and a validation set. Univariate and multivariate Cox proportional hazards regression models were used to identify independent risk factors for patients. We constructed a nomogram based on the multivariate Cox regression model to predict 1-, 3-, and 5-year CSS in patients with TYST. We used a series of validation methods to test the accuracy and reliability of the model, including the concordance index (C-index), calibration curve and the area under the receiver operating characteristic curve (AUC).

Results

619 patients with TYST were enrolled in the study. Univariate and multivariate Cox regression analysis showed that age, T stage, M stage and chemotherapy were independent risk factors for CSS. A nomogram was constructed to predict the patient's CSS. The C-index of the training set and the validation set were 0.901 (95%CI: 0.859-0.847) and 0.855 (95%CI: 0.865-0.845), respectively, indicating that the model had excellent discrimination. The AUC showed the same results. The calibration curve also indicated that the model had good accuracy.

Conclusions

In this study, we constructed the nomogram for the first time to predict the CSS of patients with TYST, which has good accuracy and reliability and can help doctors and patients make clinical decisions.

Yolk Sac Tumor in the Anterior Mediastinum Presenting as Acute Pericarditis

BACKGROUND Mediastinal masses can originate from anatomical structures normally located in the mediastinum, or from structures that travel through the mediastinum during embryogenesis. Initial presenting symptoms usually vary from shortness of breath, cough, chest pain, and superior vena cava syndrome to nonspecific constitutional symptoms (eg, fever, weight loss, fatigue). However, the initial presentation of a mediastinal mass with acute pericarditis has not been reported in the literature as far as we know. CASE REPORT A 20-year-old man presented to the Cardiology Clinic with chest pain and new pericardial effusion on echocardiography, both fulfilling the diagnostic criteria of acute pericarditis. The patient also had venous engorgement on the neck, and a chest X-ray followed by computed tomography imaging showed a large mediastinal mass. The serum tumor marker a-fetoprotein (AFP) was markedly elevated. The biopsy and immunohistochemistry revealed a high-grade malignant neoplasm - yolk sac tumor, which is a type of non-seminomatous germ cell tumor. The acute pericarditis resolved after administration of NSAID and colchicine. The patient was then started on chemotherapy. CONCLUSIONS The discussed case shows the rare presentation of an anterior mediastinal mass with acute pericarditis. This emphasizes the importance of a thorough review of systems and critical analysis of every sign and symptom at the time of initial presentation, which helps the physician to obtain appropriate imaging studies early in the course, leading to an early diagnosis and treatment of the disease, such as in this case of an extremely rare germ cell tumor.

Ultrasonic misdiagnosis of giant pediatric testicular yolk sac tumor: A case report and literature review

BACKGROUND

Yolk sac tumor is the most common malignant nonseminomatous germ-cell tumor in children characterized by elevated level of α-fetoprotein (AFP), accounting for 70%-80% of all cases. However, giant yolk sac tumors that involve the entire testicle may be misdiagnosed by color Doppler ultrasonography as orchitis. Therefore, we described a case of a 2-year-old pediatric patient with a giant testicular yolk sac tumor that was misdiagnosed by ultrasonography as orchitis, in order to evaluate the role of measuring AFP levels in the initial diagnosis to aid in the accuracy of the definitive diagnosis of testicular yolk sac tumor.

CASE PRESENTATION

A 2-year-old boy received outpatient visits for unintentional swelling of the right scrotum for 7 days. Physical examination showed a rubbery swelling of the right scrotum with rejective touch. Then, the patient underwent perineal color Doppler ultrasonography in outpatient visits. The result showed a right testicle size of 29 mm × 22 mm × 20 mm with heterogeneous echogenicity and abundant blood flow, supporting the initial diagnosis of orchitis. However, the initial surgeon was skeptical of the ultrasonography diagnosis. Thus, the patient was admitted to the Department of Andrology on day 2 for further serological and imaging examination. The serum AFP level on day 3 was 323.77 ng/ml. The results of CT and MRI showed a giant tumor of the right testis (26 mm × 21 mm × 29.6 mm) with multiple lymphoid hyperplasia in the inguinal region bilaterally. The patient received radical orchidectomy without lymph node dissection on day 9. The results of postoperative pathological examination confirmed giant testicular yolk sac tumor (T1N0M0S1, Stage Is) and was positive for AFP and SALL4 in immunohistochemistry staining. The patient received three courses of bleomycin-etoposide-cisplatin chemotherapy in the Department of Pediatrics after multidisciplinary team meeting on postoperative days 14, 37, and 58, respectively. During chemotherapy and follow-up, the patient's AFP and lactate dehydrogenase levels continued to decline, and eventually remained within normal range on postoperative day 84.

CONCLUSION

Measuring the AFP level was necessary for initial diagnosis and follow-up in pediatric cases of testicular enlargement. Radical orchidectomy combined with postoperative bleomycin-etoposide-cisplatin adjuvant chemotherapy was an effective treatment strategy for pediatric giant testicular yolk sac tumors.