Primary germ cell tumors of the mediastinum: II. Mediastinal seminomas--a clinicopathologic and immunohistochemical study of 120 cases

Primary Mediastinal Dysgerminoma: A Case Report and Literature Review

Germ cell tumors are malignant tumors that mostly develop in the gonads. Extragonadal localization is rare and may affect the mediastinal and sacrococcygeal regions. Mediastinal seminoma is a malignant germ cell tumor of the mediastinum. The tumor typically occurs in the anterosuperior mediastinum in males and often has a very slow growth pattern and limited potential for metastasis. And symptoms are not very characteristic, with many patients being asymptomatic and the tumor being discovered incidentally. In this paper, we report the case of a 26-year-old patient admitted for the management of a large anterosuperior mediastinal tumor encasing the vital structures of the mediastinum.

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges

This article will review current aspects of the histopathological, immunohistochemical and molecular analysis of primary mediastinal germ cell tumours (PMGCTs) as well as their aetiological, epidemiological, clinical and therapeutic features. PMGCTs represent an important differential diagnosis in the spectrum of mediastinal tumours, and their diagnosis is usually made on small tissue samples from core needle biopsies in combination with diagnostic imaging and serum tumour markers. As in lymphomas, a small biopsy is often the only viable tumour sample available from these patients, as they receive chemotherapy prior to eventual surgical resection. Pathologists therefore need to apply an efficient combination of immunohistochemical markers to confirm the diagnosis of a PMGCT and to exclude morphological mimics.

An update on diagnostic tissue-based biomarkers in testicular tumors

Testicular cancer is rare overall but comprises the most common solid malignancy diagnosed in young men aged ∼20-40 years. Most testicular neoplasms generally fall into 2 broad categories: germ cell tumors (GCTs; ∼95%) and sex cord-stromal tumors (SCSTs ∼5%). Given the relative rarity of these tumors, diagnostic biomarkers are highly relevant for their diagnosis. Over the past several decades, diagnostic biomarkers have improved dramatically through targeted immunohistochemical and molecular characterization. Despite these recent advances, most markers are not perfectly sensitive or entirely specific. Therefore, they need to be used in combination and interpreted in context. In this review, we summarize tissue-based biomarkers relevant to the pathologist, with a focus on practical diagnostic issues that relate to testicular GCT and SCST.

Primary mediastinal germ cell tumors

Mediastinal germ cell tumors share similar histopathological, immunohistochemical, and molecular features with their counterparts in the gonads. Therefore, proper clinical and radiological evaluation of patients with an anterior mediastinal mass becomes essential in the final interpretation of these tumors. The gold standard for the diagnosis of these tumors remains histopathological evaluation. However, immunohistochemical stains and molecular studies also provide an aid in cases in which the histology is not typical. It is also important to keep in mind that a small mediastinoscopic biopsy may not be representative of the entire neoplasm. In this review, we will provide our perspective regarding histopathological diagnosis, staging, immunohistochemical and molecular profile, and briefly family of tumors address pertinent epidemiological, clinical and treatment options. However, the main emphasis is to review the process of pathological assessment in pre and post-treated tumors. Knowledge of the different growth patterns and histological associations is important, mainly when confronted with mediastinoscopic biopsies, which ultimately will determine treatment options.

A case of soft-tissue tumor over the sternum: A rare case report

The objective is to report a rare case of extragonadal seminoma over the manubrium sterni on the chest wall. A 42-year-old male patient, a chronic alcoholic for 10 years presented with a firm mass of approximate size 10 cm × 12 cm overlying the manubrium part of the sternum. A clinical diagnosis of soft-tissue tumor was made. All relevant preoperative workup was done. Fine-needle aspiration cytology of the mass was suggestive of serous cystic lesion with chronic inflammation. Wide local excision of the mass and primary closure of the wound was done, followed by histopathological examination. Unanticipatedly, on histology, the mass turned out to be extragonadal seminoma. Postoperative wound healing was satisfactory. Subsequently, the patient underwent adjuvant chemotherapy. Primary extragonadal seminoma itself is a rare tumor that affects mainly young people with mediastinum as the most commonly involved site and has higher chances of metastasis. This case of extragonadal seminoma (extragonadal germ cell tumour) over manubrium sterni without any mediastinal involvement in a patient in early forties presenting as soft-tissue tumor, itself is a rarer entity and perhaps one of the kinds. Hence, the case needs to be reported and further progression and prevention have to be discussed.

Approach to Mediastinal Fine Needle Aspiration Cytology

Mediastinal fine needle aspirations are routinely encountered in cytopathology practice. Mediastinal lesions may pose diagnostic challenges owing to their rarity and locations associated with the complexity of the mediastinal anatomic structures in the thoracic cavity. Diagnosing mediastinal lesions and guiding patient management usually require correlating with clinical and radiologic findings, being familiar with cytomorphologic features and appropriately triaging the diagnostic material for ancillary testing. This review proposes a practical approach to interpret mediastinal fine needle aspirations and emphasizes potential diagnostic pitfalls for mediastinal lesions including benign cysts, thymic neoplasms, lymphoproliferative disorders, germ cell tumors, mesenchymal tumors, and metastatic tumors.

Survival Outcomes of Patients With Primary Mediastinal Germ Cell Tumors: A Retrospective Single-institutional Experience

BACKGROUND/AIM

Primary mediastinal non-seminomatous germ cell tumors (PMNSGCTs) are occasionally complicated by a hematologic malignancy, as with somatic-type malignant tumors called germ cell tumors with somatic-type malignancy (GCTSTM) and are known to have a poor prognosis.

PATIENTS AND METHODS

Data obtained between September 1997 and February 2020 for patients with mediastinal germ cell tumor at our institution were retrospectively analyzed. Key outcome measures included survival rates and the clinical features of non-seminoma cases.

RESULTS

Of 16 patients, 9 had pure seminoma, and 7 had non-seminoma. At the median follow-up of 56.2 months, the 5-year survival rate was significantly higher in patients with seminoma (100%) than in those with non-seminoma (37%) (log-rank test, p=0.0153). Regarding PMNSGCT, two patients evolved into GCTSTM and three had concomitant hematological malignancies.

CONCLUSION

Patients with PMNSGCTs, GCTSTM complications, and hematologic malignancies showed poor survival, suggesting the need for the development of treatment strategies.

Mediastinal germ cell tumours: where we are and where we are going-a narrative review

OBJECTIVE

In this review, we summarize the current state of the art of primary mediastinal germ cell tumours (PMGCTs) and we highlight challenges and future research directions for this disease.

BACKGROUND

PMGCTs account for 1-3% of all germ cell malignancies and for 15% of adult anterior mediastinal cancers. In 60-70% of cases PMGCTs are represented by nonseminomatous germ cell tumours (GCTs), and in 30-40% of cases by seminomas. Even if PMGCTs share histological and biochemical characteristics with gonadal GCTs, they have peculiar clinical and biological features. Nonseminomatous PMGCTs have a poor prognosis, with a 5-year overall survival (OS) rate of 40-50% after platinum-based chemotherapy and surgery, and a long-term OS of only 10% after salvage treatment. Due to the rarity of this disease, no level 1 evidence is available from randomised trials for PMGCTs. The combination of bleomycin, etoposide, and cisplatin (BEP) or etoposide, ifosfamide and cisplatin (VIP) for 4 cycles are recommended as first line treatment options for nonseminomatous PMGCTs. Surgery of the residual disease after chemotherapy is fundamental in the treatment of nonseminomatous PMGCTs. PMGCTs have high TP53 pathway gene alterations, while targetable gene alterations are rarely identified, thus challenging the advance of precision medicine in this field.

METHODS

We performed a narrative review of international literature published in English on PMGCTs, focusing the attention on clinical trials, international guidelines and translational studies.

CONCLUSIONS

Treatment of patients with PMGCTs is challenging and should be performed in experienced centers. International collaborations should become a priority to ensure optimal patient management. Clinical investigation of new therapeutic options remains an important unmet clinical need, and inclusion of patients in clinical trials should be encouraged. Liquid biopsy is a new promising strategy in PMGCTs.

Primary seminoma arising in the posterior mediastinum: a diagnostic challenge

Primary mediastinal germ cell tumors are a rare finding, and one third of them are seminomas. Seminomas are found in the anterior mediastinum, whereas they are extremely rare within the posterior compartment. Most clinicians would not consider a primary seminoma in the differential diagnosis of a posterior mediastinal mass, as only two cases have been reported in literature. Here we present the case of a 57-year-old male with a primary seminoma arising in the left posterior mediastinum. He was asymptomatic and the mass was an incidental finding. Positron emission tomography (PET) revealed a small area with an avid tracer uptake. Transthoracic needle aspiration led to a non-diagnostic result. Due to the strong suspect of malignancy, a surgical excision was chosen to obtain a diagnosis. He underwent complete excision, and pathology report demonstrated a mediastinal seminoma. Subsequent further staging did not reveal any other location of the disease. Given the complete excision of the primary tumor, active surveillance was the treatment of choice. The patient is free of disease 48 months after diagnosis.

Primary mediastinal germ cell tumours: an immunohistochemical and molecular diagnostic approach

AIMS

Primary mediastinal germ cell tumours (PMGCTs) are rare mediastinal neoplasms and their diagnosis can be challenging due to small biopsy samples. The aim of this study was to elaborate a diagnostic algorithm using immunohistochemical stainings with focus on novel markers and molecular analysis of isochromosome 12p [i(12p)].

METHODS AND RESULTS

Paraffin-embedded tissues of 32 mediastinal tumours were analysed using immunohistochemical stainings for SALL4, LIN28, OCT3/4, D2-40, CD117, SOX17, SOX2, CD30, ß-hCG, GATA3, FOXA2, GPC3, AFP, TdT, NUT and pan-cytokeratin. Quantitative real-time polymerase chain reaction (qPCR) was performed to investigate i(12p) status. Fifteen seminomas, seven teratomas, one yolk sac tumour, one choriocarcinoma and seven mixed PMGCT were diagnosed. Each entity had different immunohistochemical staining patterns which helped to distinguish them: seminoma (OCT3/4, D2-40, CD117, TdT), embryonal carcinoma (OCT3/4, SOX2), yolk sac tumour (FOXA2, GPC3, AFP) and choriocarcinoma (ß-hCG, GATA3). Mature teratomas stained positive for pan-cytokeratin in epithelial components and focally for SALL4, SOX2, GATA3, D2-40 and FOXA2. Furthermore, a NUT carcinoma mimicking a PMGCT was diagnosed showing a strong nuclear SOX2 and speckled nuclear NUT staining. i(12p) was detected in 24 out of 27 PMGCTs [89%].

CONCLUSION

A diagnostic algorithm is of great importance for a reliable diagnosis of PMGCTs in the usually small tissue biopsy samples. Therefore, a combination of three to four antibodies to identify the correct histological subtype is usually necessary in addition to morphological features. The i(12p) status serves as an additional option to underline germ cell origin in selected cases.

Thymoma: Challenges and Pitfalls in Biopsy Interpretation

The interpretation of biopsy specimens in the diagnosis of thymoma is a subject that is generally not addressed in the literature. Even though the diagnosis of thymoma may seem to be an easy step in the assessment of these tumors, in reality, it is the biopsy specimen interpretation that will be use to determine course of action in any particular patient. It may determine whether a patient is a surgical candidate or on the contrary whether a patient may be benefited the most by medical therapy. In addition, there may be conditions in which all that is required is surgical resection without any further treatment, and that the evaluation of those conditions does not necessarily required the careful pathologic staging that thymomas need. In addition, it is important to highlight that in small biopsies, there are limitations not only in terms of the cellularity and other features that may not be present in such biopsy but also the limitation in term of immunohistochemical interpretation. Herein we have attempted to highlight numerous tumoral conditions that are frequently encountered in the daily practice of mediastinal pathology, some of them pose significant problems in separating them from thymomas. Needles to say, the entire spectrum of mediastinal pathology that may at any given time mimic thymoma is well beyond the scope of this review. Furthermore, we also herein emphasize the need for proper clinical and radiologic information and correlation in order to lead to a better interpretation of the biopsy specimen. The emphasis in this review is on thymoma and their possible pitfall and shortcomings while evaluating small biopsy specimens.

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.

Diagnostic Challenges in Fine-Needle Aspiration Cytology of Mediastinal Tumors and Lesions

CONTEXT.—

Mediastinal tumors/lesions are frequently encountered in daily cytopathology practice. These lesions are accessible through endoscopic/endobronchial ultrasound-guided or computed tomography-guided fine-needle aspiration cytology and represent a wide range of primary and metastatic tumors. This often poses diagnostic challenges because of the complexity of the mediastinal anatomic structures. Tumors metastatic to mediastinal lymph nodes represent the most common mediastinal lesions and must be differentiated from primary lesions.

OBJECTIVE.—

To provide an updated review on the fine-needle aspiration cytology of mediastinal tumors/lesions, with an emphasis on diagnostic challenges. This review encompasses thymic epithelial neoplasms, mediastinal lymphoproliferative disorders, germ cell tumors, neuroendocrine tumors, soft tissue tumors, and metastatic tumors. Differential diagnoses; useful ancillary studies, including targeted immunohistochemical panels; and diagnostic pitfalls are discussed.

DATA SOURCES.—

Data were gathered from a PubMed search of peer-reviewed literature on mediastinal tumors. Data were also collected from the authors' own practices.

CONCLUSIONS.—

Fine-needle aspiration cytology plays a vital role in evaluation of mediastinal lesions. Being familiar with the clinical and cytomorphologic features of these lesions, appropriately triaging the diagnostic material for ancillary testing, and correlating with radiologic findings are important in arriving at correct diagnoses and guiding management.

Multilocular thymic cyst (MTC) and other tumors with MTC features: Pitfalls in diagnosis

Cystic lesions of the anterior mediastinum represent a well-known group of benign lesions that are relatively common in the general practice, namely in the pediatric age group. In the adult population, multilocular thymic cyst (MTC) plays an important role in occurrence as it presents as a cystic anterior mediastinal mass that clinically may mimic another anterior mediastinal tumor. In general, MTC is of rather unusual occurrence and its histopathological features have been well described in the literature. However, similar histopathological features may also be associated with a gamut of other tumoral conditions that although unrelated may be encountered growing along the walls of these cystic structures. Herein a presentation of the classical MTC and the classical histopathological features of such entity in association with other tumoral conditions will be discussed. It is highly important to underscore that the final interpretation of some of these tumors is based on a thorough evaluation of the cystic lesion and a reasonable sampling for histological evaluation so that the proper interpretation can be reached. Needless to say, the radiological and clinical information of the patients with cystic anterior mediastinal lesions is very important in the final analysis of these cases.

Nomograms for Predicting Prognosis of Primary Mediastinal Seminoma: A Population-Based Study

Objectives

Primary mediastinal seminoma (PMS) was an uncommon carcinoma, and the appropriate treatment remained controversial due to the low incidence. We aimed to investigate the demographics and tumor biological characteristics to determine the potential effective treatment and predict the prognosis.

Methods

Patients diagnosed with PMS were selected between 1975 and 2016 from Surveillance, Epidemiology, and End Results (SEER) database. Kaplan–Meier analysis and Cox proportional hazard model were conducted to determine the prognostic factors, and nomograms were employed to visually predict the prognosis. Concordance index (C-index), calibration curve, and receiver operating characteristic (ROC) curve were conducted to validate the prediction model.

Results

A total of 476 patients were included with a median age of 31 years (range, 2–76 years), and a median size of the tumor was 11.6 cm (range, 0.2–24.0 cm). The 5- and 10-year overall survival (OS) rates were 70.4% and 68.4%, respectively. Age, the extent of the primary site, metastatic status, and surgery performance were independent prognostic factors. Not received surgery was considered a poor prognostic factor for OS (HR, 1.86; 95% CI, 1.13–3.03; P=0.013). The C-index was 0.733 (95% CI, 0.685–0.781) and 0.819 (95% CI, 0.737–0.901) for internal and external validation for predicting OS, respectively. The area under the ROC curve (AUC) was 0.743 (95% CI, 0.681–0.804) for predicting OS (sensitivity, 0.532; specificity, 0.887) in the training cohort.

Conclusions

The nomogram could efficiently predict the survival of patients with PMS. Surgery was the potential effective treatment, and chemotherapy was strongly recommended for patients over 40 years.

A Case of Primary Mediastinal Seminoma Associated With Testicular Microlithiasis and Liver Injury

Mediastinal seminomas are rare neoplasms that can be found incidentally in asymptomatic patients. However, a few cases may present in the emergency room with mild to severe respiratory and/or cardiovascular symptoms. This can occur when the tumor grows large enough to cause compression and obstruction of the various structures present in the thorax. Here we present a case of a large medium mediastinal seminoma that grew to the extent of causing pulmonary artery compression which led to chronic passive backflow through the hepatic veins and hepatic congestion. This case was remarkable as well for the presence of testicular microlithiasis, a rare feature with unknown significance to date. 

Extragonadal germ cell tumors: Not just a matter of location. A review about clinical, molecular and pathological features

Extragonadal germ cell tumors (EGGCTs) are uncommon neoplasms, which arise in anatomical locations other than gonads. The pathogenesis of these neoplasms is still poorly understood and it is a matter of debate if they really represent extragondal primary neoplasms or rather extragondal metastasis from occult gonadal neoplasms. The actual observations suggest that EGGCTs represent a unique entity, so their biology and behavior are substantially different from gonadal counterparts. The diagnosis of EGGCTs is often challenging, and differential diagnosis is particularly wide. Nevertheless, a correct diagnosis is essential for the correct management of the patient. We summarize the state of art about EGGCTs, with particular emphasis on diagnosis and prognosis.

Mediastinal seminoma presenting as a neck mass falsely diagnosed as anaplastic thyroid carcinoma: A case report

Germ cell tumors can occur in the mediastinum. They account for about 20% of tumors at this location. The majority are located in the anterior mediastinum and usually occur in young adult males. Extension of mediastinal germ cell tumors into the neck with mass formation is a very rare and unusual event. Herein, we report a case of a 34 year old male who presented with a progressively enlarging neck mass. Fine Needle Aspiration (FNA) was performed as initial evaluation and showed cellular smears comprising atypical large cells with prominent irregular nucleoli and moderate amount of cytoplasm with lymphocytic infiltrate and some epithelioid granulomas in the background. The mass was misdiagnosed initially on the cytology smears as anaplastic thyroid carcinoma. The subsequent tissue core biopsy showed sheets and nests of atypical cells admixed with ill-defined granulomatous inflammation. By immunohistochemistry, the tumor cells were immunoreactive with SALL4, PLAP and OCT3/4, compatible with malignant germ cell tumor, seminomatous type. It is very rare for patients with primary mediastinal seminoma to present initially with a neck mass. Fine Needle Aspiration (FNA) of this "neck mass" can lead to misinterpretation of findings due to similarities in cytological features between malignant germ cell tumors and other undifferentiated malignant neoplasms and the diagnosis, therefore, can be very challenging.

Primary mediastinal seminoma

Background

The objective of this study was to evaluate the long term treatment results of patients with primary mediastinal seminoma.

Methods

Sixteen patients aged 21-46 diagnosed with primary mediastinal seminoma between 1983 and 2014. Mean size of the tumor was 65 cm². In all patients gonadal involvement was excluded. In 6 patients, metastases to regional lymph nodes were found and none of them presented with distant metastases. HCG was elevated in 6 patients (38%). Eight patients underwent surgery as first-line of the treatment: 7 partial and 1 complete resection of the tumor. Chemotherapy (CTH) and radiotherapy (RTH) were methods of treatment in 14 cases. Tumor was irradiated to total dose of 36.0-50.4 (median 42.5) Gy. In statistical analysis overall survival (OS) was calculated using Kaplan-Meier method.

Results

During median time of 11 years of the follow-up, complete or partial regression (PR) of the tumor was seen in all patients after primary treatment. Recurrence of the tumor was seen in 3 patients. The 5-, 10- and 15-year local control rates were 75%. One was treated with CTH, other two with RTH. All of them responded with complete regression (CR) of the tumor. Three patients died during the follow-up. All others are alive without disease. The 5-, 10- and 15-year OS was 100%, 91% and 91% respectively.

Conclusions

Chemoradiotherapy of primary mediastinal seminoma gives satisfactory treatment results with good local control rate. The treatment outcome is comparable to primary testicular seminoma.

Granulomatous reaction of primary mediastinal seminoma leading to diagnostic delay: a case report

Primary mediastinal seminoma (PMS) is a rare tumor. PMS can be morphologically related to secondary changes in the form of thymic remnants, cystic degeneration, epithelioid granulomas, fibrotic change, and syncytiotrophoblast-like cells. Ours was an interesting case where a 26-year-old male presented with an incidentally-found anterior mediastinal mass. Even though he had no pulmonary symptoms, the transthoracic co-axial needle biopsy of the mass suggested tuberculosis (TB). However, on follow-up computed tomography (CT) and magnetic resonance image (MRI) in 2 months, the mass slightly increased in size, and a small part of low density or signal intensity appeared, despite the regular anti-TB treatment regimen. Surgical resection was performed, and the resected specimens revealed scattered and irregular-shaped seminoma cells with an intervening chronic granulomatous reaction. The aim of this article is to report a case of PMS in a young male patient who had a granulomatous reaction that mimicked a neoplastic population of cells leading to an erroneous diagnosis of the small biopsy. Therefore, awareness of the secondary changes that can mimic a primary lesion can help with an early correction of this misdiagnosis.

Primary Mediastinal Pure Seminomatous Germ Cell Tumor (Germinoma) as a Rare Cause of Precocious Puberty in a 9-Year-Old Patient

Less than 5%-7% of germ cell tumors are extragonadal, with the central nervous system being the most common location in children, followed by retroperitoneum and mediastinum. Only 10% of mediastinal tumors are malignant and one-third of these are pure seminomas (germinomas). We report the case of a 9-year-old boy with development of secondary sexual characteristics. Beta-human chorionic gonadotropin was elevated and a mediastinal mass was found. Final histology showed a pure seminomatous germ cell tumor. To our knowledge, this is the first report of a boy with precocious puberty secondary to a mediastinal germinoma.

Thymoma and Synchronous Primary Mediastinal Seminomas with Florid Follicular Lymphoid Hyperplasia in the Anterior Mediastinum: A Case Report and Review of the Literature

Thymoma is the most common neoplasm of the anterior mediastinum and has malignant potential. Germ cell tumors (GCTs) found in the anterior mediastinum are usually benign, and malignant GCTs, such as seminomas, are rare. Histologically, mediastinal seminoma is indistinguishable from testicular seminoma except for site-associated morphological features such as lymphoid follicular hyperplasia. Therefore, excluding metastasis is very important. Recently, we treated a young adult patient with multiple thymic masses that occurred simultaneously. The patient underwent a thymectomy for the removal of the mediastinal masses, one of which was diagnosed as type B2 invasive thymoma, and two of which were diagnosed as primary mediastinal seminomas with massive follicular hyperplasia. The patient received adjuvant chemotherapy after surgical resection. To our knowledge, this is the first description of a thymoma and a mediastinal seminoma occurring simultaneously in the thymus. We present this case along with a literature review.

Comparison of the clinical features and hematopoietic stem cell transplantation outcomes of mediastinal malignant germ cell tumors with nonmediastinal extragonadal placements

OBJECTIVE

Even though the primary mediastinal extragonadal germ cell tumors (EGCTs) are rare, they are noteworthy in the differential diagnosis of mediastinal masses. In this study, we aimed to identify the clinical features of mediastinal malignant GCTs and compare the results of hematopoietic stem cell transplantation between mediastinal and nonmediastinal malignant EGCTs.

METHOD

Data of the patients with EGCT who were treated and underwent hematopoietic stem cell transplantation at our hospital between 1988 and 2015 were retrieved retrospectively. Results were compared between mediastinal and nonmediastinal EGCTs.

RESULTS

Data of 65 patients diagnosed with EGCT (37 [56.92%] cases with mediastinal EGCT and 28 [43.07%] cases with nonmediastinal EGCT) were assessed. The clinical stages, frequency of pretransplant status, mean pretransplant time, and mean number of chemotherapy lines before hematopoietic stem cell transplantation were not significantly different between groups. Although the overall survival did not significantly differ between groups, the 5-year survival was significantly higher in mediastinal EGCTs (P=0.02). Yolk sac tumor was significantly more common in mediastinal EGCTs (P=0.05). Mortality rates were higher in seminomas and yolk sac tumors in all cases, higher in embryonal carcinomas in mediastinal EGCT group and higher in yolk sac tumors in nonmediastinal EGCT group. While choriocarcinomas had more aggressive courses in mediastinal EGCTs, seminomas and yolk sac tumors had poorer prognosis in nonmediastinal EGCTs. Short pretransplant time and persistence of elevated posttransplant βhCG and AFP levels were the significant mortality risk factors both in mediastinal and nonmediastinal EGCTs.

CONCLUSION

Mediastinal placement of EGCT was not a poor prognostic factor; furthermore, the 5-year survival was significantly higher in mediastinal EGCTs. According to our knowledge, this is the first study that compares the clinical outcomes of hematopoietic stem cell transplantation of mediastinal and nonmediastinal malignant EGCTs.

Clinical Characteristics and Treatment Outcomes of Patients with Primary Mediastinal Germ Cell Tumors: 10-Years' Experience at a Single Institution with a Bleomycin-Containing Regimen

BACKGROUND

Cisplatin-based chemotherapy followed by surgical resection of the residual tumor remains the standard of care for patients with mediastinal germ cell tumors (MGCTs). To prevent pulmonary complications, a non-bleomycin-containing regimen is generally preferred. This study aims to review the clinical characteristics and outcomes of these patients.

METHODS

A retrospective chart review was undertaken in patients treated for MGCTs between 2003 and 2013.

RESULTS

A total of 40 patients were enrolled; 7 patients were diagnosed with seminoma, while 33 patients had non-seminoma. 92% of patients received chemotherapy as a first treatment modality: 87% bleomycin, etoposide and cisplatin; 13% etoposide and cisplatin, with an objective response rate of 61.3%. Among these, 44% achieved a complete serological response. 17 patients underwent surgical resection of the residual tumor. No patient suffered from pulmonary complications after surgery. The 5-year overall survival (OS) was 71.4 and 27.3% in seminoma and non-seminoma patients, respectively (p = 0.051). For those who received chemotherapy followed by surgical resection with no viable tumor or only mature teratoma detected, the 5-year OS was 72.7% compared with 20.7% in patients not treated with surgery (p = 0.02).

CONCLUSION

Our study confirmed the importance of a multimodality approach with primary chemotherapy followed by surgical resection of the residual tumor. A bleomycin-containing regimen can be safely used in this setting.

[One Case about Primary Mediastinal Primary Mediastinal Tumor with Mediastinal Sarcoma and Literature Review]

Primary mediastinal seminoma is a kind of germ cell malignancy outside the gonads, and it's rarer with sarcoma component. This disease which has no special clinical manifestations and imaging characteristics is difficult to identify with other mediastinal tumors and mediastinal type lung cancer. This paper reported a case of primary mediastinal seminoma with mediastinal sarcoma. Through the analysis of the diagnosis and treatment process in this patient, we will make a comprehensive review of the disease.

[Mediastinal germ cell tumors]

The mediastinum is among the most frequent anatomic region in which germ cell tumors (GCT) arise, second only to the gonads. Mediastinal GCT (mGCT) account for 16 % of all mediastinal neoplasms. Although the morphology and (according to all available data) the molecular genetics of mediastinal and gonadal GCT are identical, a number of unique aspects exist. There is a highly relevant bi-modal age distribution. In pre-pubertal children of both sexes, mGCT consist exclusively of teratomas and yolk sac tumors. The prognosis is generally favorable with modern treatment. In post-pubertal adults, virtually all patients with malignant mGCT are males; the prognosis is more guarded and depends (among other factors) on the histological GCT components and is similar to GCT in other organs. So-called somatic type malignancies (i. e. clonally related, non-germ cell neoplasias arising in a GCT) are much more frequent in mGCT than in other organs, and the association between mediastinal yolk sac tumors and hematological malignancies, such as myelodysplasias and leukemias, is unique to mediastinal tumors. The prognosis of GCT with somatic type malignancies is generally dismal.

Male Extragonadal Germ Cell Tumors of the Adult

Male extragonadal germ cell tumors (EGCTs) are characterized by a malignant transformation of germ cells without the presence of a gonadal primary tumor. EGCTs represent up to 5% of all germ cell tumors (GCTs) with an incidence around 1/1,000,000. It is assumed that EGCTs either derive from a malignant transformation of germ cells that were misdirected during embryogenesis, or from germ cells that have spread throughout the body during embryogenesis to fulfil different roles in immunological processes or distinct organ functions. EGCTs are mainly localized along the median axis, especially in the mediastinum and in the retroperitoneum. Regarding histology, they have the same subtypes as gonadal GCTs (seminomas and non-seminomas). EGCTs are normally diagnosed in advanced stages due to tumor-associated symptoms or as incidental finding during routine diagnostic or therapeutic procedures. An integral part of EGCT treatment is cisplatinum-based chemotherapy: residual tumor resection is only indicated for non-seminomatous EGCTs. The prognosis of malignant retroperitoneal EGCTs depends on tumor localization and histology. The 5-year overall survival ranges from 40% to 90% and is more favorable for retroperitoneal or seminomatous tumors than for mediastinal non-seminomatous tumors. Mature teratomas of mediastinal EGCTs are benign and are only treated by surgical resection.

Role of radiotherapy in treating patients with primary malignant mediastinal non-seminomatous germ cell tumor: A 21-year experience at a single institution

Background

The aim of this study was to investigate the clinical characteristics and outcomes of patients with primary malignant mediastinal non-seminomatous germ cell tumor (MMNSGCT) by comparing the efficacies of different treatment modalities.

Methods

The charts of 62 consecutive patients with MMNSGCT between 1990 and 2010 were reviewed. Analyses included Kaplan-Meier survival and Cox multivariate regression.

Results

There was sufficient data of 61 patients for inclusion in the study. The median age was 25 years. At diagnosis, 35 patients had tumors located in the mediastinum, 26 had lung and/or distant metastases. At a median follow-up of 47.2 months, 32 patients had died and 43 had developed progressive disease. The one, three, and five-year overall survival (OS) and progression-free survival (PFS) rates were 72.1%, 50.8%, 49.2% and 47.5%, 32.8%, 32.8%, respectively. Patients who received radiotherapy in the primary treatment regimen showed improved five-year OS (68.2% vs. 38.5%, P = 0.043), PFS (45.5% vs. 20.5%, P = 0.023), and local recurrence-free survival (LRFS) (77.3% vs. 38.5%, P = 0.003) compared with those who did not receive radiotherapy. Multivariate analysis revealed that radiotherapy was an independent prognostic factor of five-year OS (hazard ratio [HR] 0.39, P = 0.037), PFS (HR 0.42, P = 0.017), and LRFS (HR 0.31, P = 0.019).

Conclusion

Radiotherapy in a chemotherapy-based treatment regimen could significantly reduce local recurrence and improve survival of MMNGCT patients.

Primary mediastinal seminomas: a comprehensive immunohistochemical study with a focus on novel markers

Primary mediastinal seminomas are unusual tumors that can present in a pure form or as part of a mixed germ cell tumor. Contrary to testicular seminomas, little is known about the expression of novel immunohistochemical markers in mediastinal seminomas. This study investigates the immunohistochemical features of these tumors with a focus on novel markers. Thirty-two cases of primary mediastinal seminomas were reviewed; and representative whole-tissue sections were selected for immunohistochemical studies using antibodies directed against high molecular weight cytokeratin 5/6 (CK5/6), low molecular weight cytokeratin (CAM5.2), octamer-binding transcription factor 3/4 (OCT3/4), spalt-like transcription factor 4 (SALL4), GATA binding protein 3 (GATA-3), sry-related HMG box 2 (SOX2), SOX17, human T cell leukemia/lymphoma 1 (TCL1), glypican 3, melanoma associated antigen C2 (MAGEC2), and paired box gene 8 (Pax8). The percentage of positive tumor cells as well as the intensity of staining was evaluated and scored. Thirty-one cases (97%) expressed SOX17, whereas 29 cases (91%) were positive for OCT3/4 and SALL4, respectively. Twenty-eight cases (88%) expressed MAGEC2 and CAM5.2, respectively. Two cases (6%) were positive for Pax8, and a single case (3%) was positive for TCL1. None of the cases stained with CK5/6, GATA-3, SOX2, or glypican 3. Similar to testicular seminomas, mediastinal seminomas show consistent expression of OCT3/4, SALL4, SOX17, and MAGEC2 and are negative for SOX2, glypican 3, GATA-3, and CK5/6. Pax8 positivity is only inconsistently identified in mediastinal seminomas. Contrary to their testicular counterparts, mediastinal tumors show diffuse expression of low-molecular-weight cytokeratin in up to 90% of cases and are commonly negative for TCL1. Although there is some immunohistochemical overlap between testicular and mediastinal seminomas, considerable differences also exist and should be acknowledged when dealing with these tumors.

Combined thymoma-thymic seminoma. Report of 2 cases of a heretofore unreported association

Two cases of a primary mediastinal tumor showing both thymoma and seminoma elements are presented. The patients were 2 men, aged 32 and 34 years, respectively. Clinically, both patients presented with symptoms related to their mediastinal masses, namely, chest pain and shortness of breath. Neither patient had any previous history of malignancy elsewhere. Diagnostic imaging revealed the presence of large anterior mediastinal masses. Both patients underwent thoracotomy with complete resection of their tumors. Grossly, the lesions measured 6 and 8 cm in greatest diameter, respectively and were tan and firm without areas of hemorrhage or necrosis. Both tumors appeared to be well circumscribed and grossly not involving any adjacent structures. Histologic sections showed the presence of distinct areas in the same tumor mass corresponding to conventional thymoma, whereas other areas corresponded to seminoma. Both components appeared to be present in almost equal proportions in the tumor. Immunohistochemical studies showed distinct labeling for each component: the thymoma component was positive for CAM5.2, Pax8, and cytokeratin 5/6; the seminoma component was positive for CAM5.2, SALL4, OCT3/4, and placental-like alkaline phosphatase. Both patients are currently alive and well 12 and 18 months after surgery, respectively. The cases herein described highlight the importance of ample sampling in mediastinal tumors and document for the first time the existence of combined thymoma-thymic seminomas.

Management of the primary malignant mediastinal germ cell tumors: experience with 54 patients

Background

Primary malignant mediastinal germ cell tumor (PMMGCT) is rare and sometimes the prognosis of the patients with PMMGCT is not very satisfactory.

Methods

A total of 54 patients with PMMGCT in a follow-up from 1990 to 2009. We evaluated the role of the surgical treatment and the effect of multimodality treatment strategy for patients with PMMGCT.

Results

Fifty-two patients underwent surgical resections, while the other two patients just received chemoradiotherapy. Among the 52 patients, 28 cases received preoperative adjuvant therapy and 24 cases underwent surgery as initial treatment; 30 cases with complete resections, 18 cases with partial resections and 4 cases with only biopsies. There was no perioperative mortality. Histopathologic results revealed 18 cases of seminomas and 36 cases of nonseminomatous germ cell tumors (NSGCT). The last follow-up showed that 17 patients were alive, including 11 patients with seminoma and 6 patients with NSGCT. The 5-year overall survival rate of patients with seminomas was 87.7%. The 3-year and 5-year overall survival rates of patients with NSGCT were 47.4% and 23.0%, respectively.

Conclusions

It could be concluded that a complete surgical resection of PMMGCT after chemoradiotherapy showed favorable long-term survival. Patients with pure seminomas have a better prognosis compared with that with NSGCT.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1676987232116837.

Extragonadal germ cell tumors: clinical presentation and management

PURPOSE OF REVIEW

The extragonadal germ cell tumors (EGCTs) represent a unique entity, and as such require specialized management. This review article will discuss the diagnosis, prognosis and treatment modalities for EGCTs.

RECENT FINDINGS

The anterior mediastinal germ cell tumors (GCTs) are the most common EGCT. These tumors originate in the anterior mediastinum without any testis primary. Mediastinal nonseminomatous GCTs carry a poor prognosis with 40-50% overall survival and should be treated with cisplatin-based chemotherapy followed by surgical resection of the residual tumor. At Indiana University, we recommend etoposide (VP-16), ifosfamide and cisplatin (VIPx4) instead of bleomycin, etoposide and platinum (BEPx4) to prevent pulmonary complications, as these patients require extensive thoracic surgical resection. Patients who relapse have a dismal outcome with only 10% long-term survival. Our preferred treatment option is surgery for localized relapse; if surgery is not feasible, then high-dose chemotherapy with stem cell transplant in an experienced center is a reasonable approach. Retroperitoneal GCT should be treated in a similar fashion to primary testis cancer.

SUMMARY

The utilization of cisplatin-based chemotherapy is associated with the best chance of cure for EGCTs. This should be followed by surgical resection of residual tumor in nonseminomatous GCT.

Establishment and characterization of a new human extragonadal germ cell line, SEM-1, and its comparison with TCam-2 and JKT-1

OBJECTIVE

To describe the establishment and characterization of a human cell line, SEM-1, from a patient diagnosed with a mediastinal seminoma.

METHODS

A small percentage of germ cell tumors develop as primary lesions in extragonadal sites, and the etiology of these tumors is poorly understood. Currently, only 2 cell lines from seminoma patients have been reported, JKT-1 and TCam-2, both derived from the testis. The cell line was characterized by heterotransplantation in Nude mice, cytogenetic studies, immunohistochemical and flow cytometry staining for germ cell tumor biomarkers, quantitative reverse-transcription polymerase chain reaction for cancer testis antigen expression, and BRAF mutation screening with quantitative polymerase chain reaction.

RESULTS

Characterization studies confirmed the human extragonadal seminoma origin of SEM-1 and demonstrated that it had more features in common with TCam-2 than JKT-1. Specifically, SEM-1 was positive for Sal-like protein 4 (SALL-4), activator protein-2γ (AP-2γ), and cytokeratin CAM5.2, and demonstrated heterogeneous expression of stem cell markers octamer-binding transcription factor 3/4, NANOG, c-KIT, SOX17, and SOX2. Cytogenetic analysis revealed a hypotriploid chromosome number, with multiple copies of 12p, but isochromosome 12p and the BRAF mutation V600E were not identified. The cell lines also did not contain the BRD4/NUT gene rearrangement [t(15,19)] seen in midline carcinomas nor did they contain overexpressed nuclear protein in testis (NUT) genes.

CONCLUSION

SEM-1 is the first cell line derived from an extragonadal germ cell tumor showing intermediate characteristics between seminoma and nonseminoma, and as such, is an important model to study the molecular pathogenesis of this malignancy.

A case report of mediastinal seminoma arising after renal transplantation

Recipients of organ transplantation on immunosuppressive medications are at increased risk for developing de novo malignancies, including skin cancer, Kaposi's sarcoma, in situ carcinomas of the uterine cervix, anogenital cancers, renal cell carcinoma, and post-transplant lymphoproliferative disorders (PTLD). However, there are few case reports of germ cell tumors after organ transplantation. There are some case reports of testicular seminoma, but not mediastinal seminoma. This case report is the first description of a mediastinal seminoma that developed de novo 28 months after renal transplantation and that was initially diagnosed as PTLD. To improve outcomes of organ transplant recipients, it is important to report rare cases of malignancies arising while on immunosuppressive medications. When we detect mediastinal tumor arising after organ transplantation while on immunosuppressive therapy, diseases other than PTLD should be considered in the differential diagnosis.

Micronodular thymic carcinoma with lymphoid hyperplasia: a clinicopathological and immunohistochemical study of five cases

Five cases of an unusual variant of thymic carcinoma are described, which represent the counterpart of the so-called micronodular thymoma with lymphoid hyperplasia. The patients were three men and two women aged 42-78 years (mean 64 years). Three patients were asymptomatic and the tumors were found incidentally on chest radiographs performed for unrelated reasons. Two patients complained of dyspnea, chest pain and shortness of breath prompting further investigations. The tumors ranged in size from 3.2 to 10.0 cm and were described as infiltrative masses often invading adjacent structures. Prominent cystic changes were not identified. Histologically, the neoplasms were composed of epithelial tumor cells arranged in a micronodular growth pattern set in a stroma showing florid lymphoid hyperplasia. Contrary to micronodular thymoma, the epithelial cell component of the present cases showed unequivocal signs of malignancy characterized by cytological atypia and increased mitotic activity. Immunohistochemical studies showed the lymphoid component to be of mixed B- and T-cell lineage. None of the patients had a history of myasthenia gravis or other autoimmune disorder. Follow-up revealed that 4 patients were alive and well 3-26 months after diagnosis while 1 patient was dead of disease 21 months after diagnosis. The tumors in this series represent a distinct subtype of thymic carcinoma histologically strongly resembling micronodular thymoma with lymphoid hyperplasia. Awareness of this type of thymic carcinoma is important in order not to dismiss this tumor for a neoplasm of lower-grade malignancy.

Primary mediastinal "thymic" seminomas

Over the last half century, our knowledge on germ cell tumors (GCT) has increased dramatically. Tumors that at one time were supposed to originate exclusively from certain anatomic areas are now thought to occur in ubiquitous distribution. Nevertheless, because of their similar histopathologic features, the conventional classic evaluation of these patients will require careful clinical history as well as complete physical and radiologic evaluation. The emphasis in this manuscript will be to highlight the occurrence and overall characteristics of one of the most common GCTs in the mediastinal region-seminoma. A more detailed discussion of mediastinal GCTs is well beyond the scope of this review.

High-dose chemotherapy with autologous PBSC transplantation for poor prognosis germ cell tumors: a retrospective monocenter analysis of 44 cases

Germ cell cancer (GCC) is curable in metastatic stages. The International Germ Cell Cancer Collaborative Group (IGCCCG) reports a poor prognosis subgroup with a 5-year survival of 48%. High-dose chemotherapy with PBSC transplantation (HD-PBSCT) in these patients showed promising results in phase II, but failed to show significant advantage in randomized trials. We report our monocenter series of all poor and selected intermediate prognosis germ cell tumor patients treated with multiple-course HD-PBSCT and secondary surgery of remaining tissue. We performed a retrospective analysis of our complete series of 44 patients (40 poor prognosis and 4 intermediate prognosis) treated by HD-PBSCT as part of first-line therapy from 1999 to 2010. The CR rate after up to four cycles of HD-PBSCT and radical resection of residual manifestations was 73%. The 3-year survival rate was 79.5% (median follow-up of 51.5 months; range: 7-143 months). Disease-related death rate was 16%. HD-PBSCT-related death did not occur. One patient died postsurgery. Multiple courses of HD-PBSCT with radical secondary surgery is safe and effective in poor prognosis metastatic GCC. Despite disappointing phase III studies it is of high interest to further study this field.

Mediastinal dysgerminoma complicating pregnancy

Malignancy complicating pregnancy represents one of the most challenging clinical situations. Lack of evidence and the presence of the dependent fetus contribute to the management dilemma. A 26-year-old primigravida presented at 23 weeks of gestation with a bulging substernal mass. Fine-needle aspiration was reported as mediastinal dysgerminoma. She was treated with weekly bleomycin and three weekly cisplatin and etoposide (BEP). Maternal neutropenia after 11 weeks of bleomycin required colony stimulator factor. Fetal growth restriction necessitated delivery at 31 weeks. Significant clinical and radiological tumour regression was noted after chemotherapy. Postnatally mother received external beam radiotherapy but the disease worsened two weeks after the completion of radiotherapy. Mediastinal dysgerminoma differs from the ovarian counterpart and therefore therapeutic success reports on ovarian germ cell tumours complicating pregnancy cannot be extrapolated. The safety of the BEP regimen for the fetus is yet to be established.

Treatment strategies and prognostic factors of patients with primary germ cell tumors in the mediastinum

OBJECTIVE

The aim of this study was to evaluate the clinical characteristics and survival outcomes of patients with primary mediastinal germ cell tumor (PMGCT) by identifying the prognostic factors and efficacies of different treatment modalities.

METHODS

Fifty-five patients with PMGCT who were treated consecutively at Cancer Center, Sun Yat-sen University, Guangzhou, from 1988 to 2010 were evaluated retrospectively.

RESULTS

Fifty-two men and 3 women with a median age of 25 years were identified, of whom 17 (30.9%) had pure seminomatous, 38 (69.1%) had nonseminomatous histology, 27 (49.1%) had tumor located at mediastinum, 20 (36.4%) had lung metastases and/or effusions, and 8 (14.5%) had distant metastases. Three treatments surgery, chemotherapy, and radiotherapy were performed in 11 (20%) patients, two treatments chemotherapy plus surgery or radiotherapy were performed in 25 (45.6%), and single treatment surgery or chemotherapy was performed in 17 (30.9%). The other two patients (3.6%) received no treatment. After a median follow-up time of 31.4 months, the 5-year survival rate was 52%. The median overall survival time was 87.9 months. Patients who received two treatments had the longest survival time of 118.3 months, P = 0.000. Those who had pure seminoma histology, whose tumor confined to the mediastinum and who achieved complete or partial remission at initial evaluation, who had complete resection and radiotherapy were considered to have better prognosis according to univariate analysis. On multivariate analysis, extension and response rate at initial evaluation were independently predictive of survival.

CONCLUSIONS

Primary mediastinal germ cell tumor is rare with a dominant frequency in young male patients. Chemotherapy combined with local therapy like surgery or radiotherapy is a reasonable treatment strategy recommended. Extension and initial remission rate are independent prognostic factors.

Oral metastasis of the mediastinal germ cell tumor (yolk sac)

A yolk sac tumor is a rare malignant tumor of germ cell origin. It most commonly arises from the testes and ovaries in young adults, but extragonadal sites of origin are reported in 10% to 15% of the cases. Yolk sac tumors are malignant, tend to recur locally, and may present with widespread metastases at the time of diagnosis. Involvement of the head and neck is uncommon. In this study, we present the case of a 23-year-old man presenting with mandibular and adjacent gingival metastasis of a mediasatinal yolk sac tumor. Thus, the patient has already undergone chemotherapy; no additional treatment was provided. In this case report, clinical and histopathologic features of the oral metastases of a yolk sac tumor were briefly discussed.

RNA-binding protein LIN28 is a marker for primary extragonadal germ cell tumors: an immunohistochemical study of 131 cases

LIN28 has been shown to have an important role in primordial germ cell development and malignant transformation of germ cells in mouse. In this study, we examined the immunohistochemical profile of LIN28 in 131 primary human extragonadal germ cell tumors (central nervous system (CNS) 76, mediastinum 17, sacrococcygeal region 30, pelvis 3, vagina 2, liver 1, omentum 1, and retroperitoneum 1), including the following tumors and/or components: 57 seminomas/germinomas, 10 embryonal carcinomas, 74 yolk sac tumors, 6 choriocarcinomas, 15 mature, and 13 immature teratomas. We compared LIN28 with SALL4 to assess its diagnostic value. To determine its specificity, we examined LIN28 in 406 extragonadal-non-germ cell tumors (103 carcinomas, 91 sarcomas, 9 melanomas, 12 mesotheliomas, 83 lymphomas, 9 plasmacytomas, 82 CNS tumors, and 17 thymic epithelial tumors). The staining was semi-quantitatively scored as 0 (no cell stained), 1+ (0-30%), 2+ (31-60%), 3+ (61-90%), and 4+ (>90%). LIN28 staining was seen in all seminomas/germinomas (3+ in 1 and 4+ in 56), embryonal carcinomas (4+ in all 10), and yolk sac tumors (3+ in 3 and 4+ in 71). Variable LIN28 staining was seen in 5 of 6 choriocarcinomas (1+ to 4+), 8 of 13 immature teratomas (1+ to 2+ in immature elements), and in 1 of 15 mature teratomas (1+). Only 11 of 406 non-germ cell tumors showed 1+ LIN28 staining. Therefore, LIN28 is a sensitive (100% sensitivity) marker for primary extragonadal seminomas/germinomas, embryonal carcinomas, and yolk sac tumors with high specificity. Compared with SALL4, LIN28 demonstrated a similar level of diagnostic sensitivity for seminomas/germinomas and embryonal carcinomas. For primary extragonadal yolk sac tumors, although SALL4 stained all tumors (1+ in 1, 2+ in 2, 3+ in 10, and 4+ in 61), LIN28 stained more tumor cells (mean 95 vs 90%, P = 0.03) and was therefore more sensitive. For primary extragonadal yolk sac tumors, combining LIN28 and SALL4 can achieve a higher diagnostic sensitivity than either alone.

Survival outcomes for men with mediastinal germ-cell tumors: the University of Texas M. D. Anderson Cancer Center experience

OBJECTIVE

Primary mediastinal germ-cell tumors are rare, and the effect of newer drugs and treatment strategies in this disease on overall survival is not known. We retrospectively assessed treatment outcomes at a single institution.

MATERIALS AND METHODS

We identified men seen at our institution from 1998 through 2005 for mediastinal germ-cell tumors. Medical records were reviewed for patient characteristics, histology, tumor markers, treatment, and survival outcome.

RESULTS

Thirty-four patients met study criteria, of whom 27 had nonseminomatous germ-cell tumor (NSGCT) and 7 had pure seminoma. Eleven patients (41%) with NSGCT were alive at last contact with a median overall survival time of 33.5 months. Among 13 patients with NSGCT referred to us at initial diagnosis, 7 (54%) were alive and recurrence-free at a median follow-up of 56.5 months. Progression-free survival was associated with absence of risk factors (any histology other than endodermal sinus tumor, β-hCG > 1000 mIU/mL, or disease outside the mediastinum). For the patients whose disease progressed (n = 5) or who had been referred to us for salvage treatment (n = 14), the 3-year overall survival from the date of first progression was 23%. Conversely, patients with seminoma did uniformly well with platinum-based chemotherapy; most did not undergo radiation or surgery.

CONCLUSION

Chemotherapy given to maximum effect followed by surgical consolidation resulted in long-term progression-free survival for 54% of patients with mediastinal NSGCT. The number of risk factors present at diagnosis may be associated with survival outcome and should be studied in a larger test group.

Tumors of the mediastinum and chest wall

Primary tumors of the mediastinum and chest wall comprise a diverse group of conditions with a wide range of presentations. A thorough knowledge of thoracic anatomy is essential for appropriate diagnosis and treatment. Given their proximity to critical structures, treatment of these tumors is often challenging. Although surgery is the mainstay of therapy for most mediastinal and chest wall tumors, a multidisciplinary approach is valuable in many cases.