Mediastinal Germ Cell Tumors: Updates in Diagnosis and Management

Pure mediastinal seminoma about a case report

Mediastinal Seminoma is one of the malignant germ cell tumors of the mediastinum. It is a rare tumor that represents only 1%-4% of mediastinal tumors. We report the case of a patient treated at the Oncology Center of Oujda for a pure primitive seminoma of the mediastinum, with a review of the literature to assess the epidemiological, clinical, therapeutic, and prognostic characteristics of this pathology. This is a 25-year-old man whose aunt is being treated for breast cancer and who complained of persistent dry cough with asthenia without any other associated signs. The initial imaging revealed a voluminous locally advanced tumor process in the anterior and middle mediastinum. Tumor markers Alpha-fetoprotein (AFP) and beta-subunit of chorionic gonadotrophic hormone (BHCG) were normal, as well as testicular ultrasound. The CT- guided transthoracic biopsy with anatomopathological study and immunohistochemistry was in favor of a pure seminoma. The treatment consisted of primary chemotherapy with BEP protocol. The response was favorable with a significant reduction in tumor size estimated at 90%. The residual tumor was inoperable due to its intimate contact with the vascular structures and was treated with external radiotherapy at a total dose of 36 Gy. The evolution at 20 months after treatment was in favor of a good clinical and radiological evolution.

Growing Teratoma Syndrome—A Clinicoradiological Series

Context Growing teratoma syndrome (GTS) is a rare entity seen following chemotherapy for metastatic nonseminomatous germ cell tumors, characterized by increase in size of the metastatic deposits, with normal serum tumor markers.

Aims In this article, we aim to describe the various clinicoradiological presentations of GTS treated at our center.

Design All patients who satisfied the GTS criteria from 2001 to 2019 were included. Characteristic imaging appearances along with sites of primary lesion and metastatic disease, stage and risk stratification at diagnosis, details of chemotherapy, details of surgical treatment and histopathology, levels of tumor markers, serum β-human chorionic gonadotropin, lactate dehydrogenase, and alpha fetoprotein levels at baseline and at the end of all chemotherapy were analyzed.

Results The significant radiological findings observed were an increase in the fat and cystic components and appearance of coarse calcifications within the lesions. Majority of the cases were male patients (87.5%) with testicular primaries and GTS transformation in nodal metastases being the most common occurrence (75%). All eight cases (100%) showed an increase in size and cystic component, whereas four out of eight cases (50%) had presence of internal septations and internal calcification.

Conclusion Early recognition of this entity and clinical decision making through serial radiological imaging are of utmost importance as these growing deposits are resistant to chemotherapy and radiotherapy, with complete surgical excision being the only curative and definitive treatment option.

Standard versus high-dose chemotherapy in mediastinal germ cell tumors: a narrative review

OBJECTIVE

The aim of this review is to analyze feasibility and toxicities of high-dose chemotherapy (HDCT) in comparison to standard dose chemotherapy (SDCT) in patients affected by mediastinal germ cell tumors (MGCTs), discussing factors that may affect therapeutic choices, such as: management of residual disease, early response predictors for chemotherapeutic efficacy and determinants of chemotherapeutic resistance. In this review, we discuss the main clinical experiences with HDCT and SDCT in germ cell tumor (GCT) patients specifically in those affected by MGCT.

BACKGROUND

MGCTs represent a very small subset characterized by a poor prognosis, despite improvements in their clinical management and in understanding their biology. From early 1970s, HDCT has become an alternative to SDCT for both first-line and salvage therapeutic settings in advanced GCT patients. Several HDCT schedules-either cisplatin or carboplatin-based-have been tested so far, both in clinical randomized trial and in single-center experiences, with divergent results in terms of clinical outcomes and tolerability. Moreover, the majority of these studies included, but were not exclusively designed for, advanced MGCT patients, making difficult to infer data for this specific subset.

METHODS

an extended review of literature through PubMed was conducted using the keywords "mediastinal germinal cell tumors", "standard dose chemotherapy" and "high dose chemotherapy".

CONCLUSIONS

HDCT regimens could not be considered to date a standard option as first-line therapy in advanced MGCT patients, whilst they could be an alternative to SDCT regimens in relapsed tumors after proper patient selection.

Clinicopathological Features and Prognosis of Primary Mediastinal Malignant Germ Cell Tumors: A Retrospective Single-Institution Analysis

Background

Given the lack of evidence-supported guidance for therapeutic recommendations of primary mediastinal malignant germ cell tumors (PMMGCTs), our study aimed to investigate the clinicopathological features, treatment strategies, and prognostic factors of PMMGCTs.

Methods

We carried out a consecutive retrospective evaluation on a series of patients diagnosed with PMMGCTs in Peking Union Medical College Hospital from January 2000 to August 2020.

Results

A total of 58 patients were eligible, consisting of 51 males and seven females. There were 15 patients with seminomas, 39 with nonseminomatous germ cell tumors (NSGCTs), and four with mixed germ cell tumors (GCTs). The 5-year overall survival was 45%, with a median survival time of 32.37 months. Except for the lost follow-up of seven patients, a univariate analysis of overall survival on the remaining patients showed significant differences in pathological type (mixed GCTs were regarded as NSGCTs) (p=0.036), tumor size (>11cm) (p=0.006), and other sites metastases (OSM) (p=0.001), respectively. Multivariate Cox regression analysis revealed that OSM and surgical resection were independently associated with overall survival in all kinds of PMMGCTs.

Conclusion

OSM was an independent risk factor for patients with PMMGCTs. Surgery was proved to contribute to long-term survival. More in-depth clinical evidence is urgently needed to guide the treatment of PMMGCTs.

Mediastinal Germ Cell Tumors: A Review and Update on Pathologic, Clinical, and Molecular Features

Mediastinal germ cell tumors (MGCTs) are the most common extragonadal germ cell tumors (GCTs) and most often arise in the anterior mediastinum with a male predilection. MGCTs also have a predilection for patients with Klinefelter syndrome and possibly other genetic conditions. MGCTs, as GCTs at other extragonadal sites, are thought to arise from germ cells improperly retained during migration along the midline during embryogenesis. Similar to their counterparts in the testes, MGCTs are classified into seminomatous and nonseminomatous GCTs. Seminomatous MGCT represents pure seminoma, whereas nonseminomatous MGCTs encompass pure yolk sac tumors, embryonal carcinoma, choriocarcinoma, mature or immature teratoma, and mixed GCTs with any combination of GCT types, including seminoma. Somatic-type or hematologic malignancies can also occur in association with a primary MGCT. MGCTs share molecular findings with GCTs at other sites, most commonly the presence of chromosome 12p gains and isochromosome i(12p). Treatment includes neoadjuvant chemotherapy followed by surgical resection of residual tumor, with the exception of benign teratomas, which require only surgical resection without chemotherapy. In this review, we highlight and provide an update on pathologic, clinical, and molecular features of MGCTs. Immunohistochemical profiles of each tumor type, as well as differential diagnostic considerations, are discussed.