Hematologic malignancies associated with primary mediastinal germ-cell tumors

Second Hematologic Malignancies Associated With Primary Mediastinal Germ Cell Tumors: A Population-based Study

BACKGROUND

Studies addressing second hematologic malignancies (SHMs) in patients with primary mediastinal germ cell tumors (PMGCTs) are scarce. To better describe this phenomenon, we analyzed a large case series from a population-based registry.

METHODS

The Surveillance, Epidemiology, and End Results database was used to report the clinical characteristics and incidence of SHMs in patients with PMGCT.

RESULTS

Among 1297 PMGCTs, 27 cases (2.08%) of SHM were found, with a median latency period of 12 months (95% CI: 5-41). All SHM occurred in males, 20 of whom (74.1%) had a previous nonseminomatous tumor. Acute myeloid leukemia was the most frequent SHM, accounting for 13 cases, 4 of which were acute megakaryoblastic leukemia that occurred within 5 months of diagnosis. The median survival after the diagnosis of SHM was 6 months (95% CI: 2-41). The risk of SHM was significantly higher than expected for the reference population, with a standardized incidence ratio of 6.21 (95% CI: 3.31-10.62) and an absolute excess risk of 19.19 per 10,000 person-years.

CONCLUSIONS

Patients with PMGCT are at a higher risk of developing SHMs than the general population, particularly acute myeloid leukemia. This risk ranges from synchronous diagnosis of acute megakaryoblastic leukemia to the later onset of other hematological disorders that might be related to PMGCT therapies. Our findings may help create follow-up schedules for patients with PMGCT and raise the level of suspicion surrounding this association.

Gene mutation landscape of a rare patient with acute megakaryoblastic leukemia after treatment of intracranial germ cell tumor

Introduction

It was first reported that germ cell tumor patients suffer from hematologic malignancies 37 years ago. Since then, the number of relevant reports has increased each year, with most cases being mediastinal germ cell tumor. Theories have been proposed to explain this phenomenon, including a shared origin of progenitor cells, the effects of treatment, and independent development. However, up to now, no widely accepted explanation exists. The case with acute megakaryoblastic leukemia and intracranial germ cell tumor has never been reported before and the association is far less known.

Methods

We used whole exome sequencing and gene mutation analysis to study the relationship between intracranial germ cell tumor and acute megakaryoblastic leukemia of our patient.

Results

We report a patient who developed acute megakaryoblastic leukemia after treatment for an intracranial germ cell tumor. Through whole exome sequencing and gene mutation analysis, we identified that both tumors shared the same mutation genes and mutation sites, suggesting they originated from the same progenitor cells and differentiated in the later stage.

Discussion

Our findings provide the first evidence supporting the theory that acute megakaryoblastic leukemia and intracranial germ cell tumor has the same progenitor cells.

Primary mediastinal germ cell tumors (PMGCT): A real-world analysis from a tertiary cancer care centre in India

BACKGROUND

Primary mediastinal GCT (PMGCT) is a rare entity and comprises 10-15% of all mediastinal tumors . We present our institutional experience of MGCT treated with multimodality management.

MATERIALS AND METHODS

We conducted a retrospective analysis between 2010 to 2020 of all mediastinal germ cell tumors registered at our center. Data on patient demographics, treatments received, treatment toxicities and response were recorded. Overall survival and relapse free survival were estimated using Kaplan-Meier methods.

RESULTS

A total of 30 patients were identified. The median age was 25.5 (range, 18-45) years. Common presenting features included cough (70%) and shortness of breath (70%) . Histology wise, 60% patients were non seminomatous histology whereas 33.3% patients were Seminoma.Twenty seven (90%) patients received chemotherapy as the first-line treatment, of whom five patients (16.6%) underwent surgery and radiation therapy subsequently. Median follow-up was 26.9 months. Thirteen patients (43.3%) had complete response (43.3%) and 8 patients had partial response (26.7%), while three patients (5.5%) had progressive disease. Three year relapse free survival rate was 69.6% (95% confidence interval [CI], 42.8-85.6%). Overall survival (OS) at 3 years was 73.4% (95% CI, 49.4- 87.3%). Patients with seminoma had a 3 year OS of 90.0% (95% CI, 47.3-98.5%) compared to those with non-seminoma (63.53% [95% CI, 32.3-83.3%]).

CONCLUSIONS

Multiagent chemotherapy is the backbone of treatement in PMGCT. Seminomatous PMGCT have excellent prognosis, while further improvement is needed in those with non-seminomatous tumor.

Atypical cartilage in type II germ cell tumors of the mediastinum show significantly different patterns of IDH1/2 mutations from conventional chondrosarcoma

Neoplastic cartilage is a common component of teratomas in type II germ cell tumors. Although IDH1/2 mutations have been well-described in somatic cartilaginous tumors, ranging from benign enchondromas to highly aggressive dedifferentiated chondrosarcomas, the presence of IDH1/2 mutations in cartilaginous neoplasms arising from germ cell tumors has not been previously investigated. To better understand the relationship between these tumors and their bone/soft tissue counterpart, we studied the IDH1/2 mutational status of 20 cases of primary mediastinal mixed germ cell tumors with areas of readily identifiable cartilaginous differentiation. Our study found that cartilaginous lesions arising in germ cell tumors have a different frequency and distribution of IDH1/2 mutations compared to those at somatic sites. We identified IDH1/2 mutations in only 15% (3/20) of cases, compared to a frequency in the literature among differentiated chondroid tumors of bone and soft tissue of 54%, a highly significant decreased frequency (p = 0.0011; chi-square test). Furthermore, they were exclusively IDH2 R172 mutations that occurred at a non-significant, increased frequency in the germ cell tumor group compared to conventional chondrosarcoma (15% vs. 5%, respectively, p > 0.05, chi-square test). The unexpected finding, therefore, was entirely attributable to the absence of IDH1 R132 mutation in chondroid neoplasia of germ cell origin (p < 0.00001, Fisher exact test). Our results suggest that a subset of cartilaginous lesions arising within type II germ cell tumors have a similar oncogenic mechanism to their bone/soft tissue counterpart but that the majority form using different oncogenic mechanisms compared to their somatic counterparts.

Malignant histiocytosis associated with mediastinal germ cell tumor: A case report

BACKGROUND

Germ cell tumors (GCTs) account for 2% of human malignancies but are the most common malignant tumors among males aged 15-35. Since 1983, an association between mediastinal GCT (MGCT) and hematologic malignancies has been recognized.

CASE SUMMARY

We report a case in which malignant histiocytosis was associated with mediastinal GCTs. The clinical data of a male patient with MGCT admitted to Beijing Children's Hospital were collected retrospectively. The patient was first diagnosed according to imaging and pathological features as having MGCT, and was treated with surgery and chemotherapy. One year after stopping chemotherapy, imaging showed metastases in the right supraclavicular, mediastinum, hilar region and retroperitoneal lymph node, right pleura, right lung, and right para-cardiac margin. Pathological diagnosis of the liver nodular and hilar lymph nodes included systemic juvenile xanthogranuloma and Rosai-Dorfman lesions with malignant transformation (i.e., morphological characteristics and immunophenotype of histiocytic sarcoma). Following diagnosis, the patient accepted chemotherapy with vindesine, cytarabine and dexamethasone. Positron emission tomography–computed tomography showed partial remission. The patient was followed-up for 10 mo after the diagnosis of malignant histiocytosis, and no sign of progression or relapse was observed.

CONCLUSION

Physicians should recognize the possibility of hematologic malignancies being associated with MGCT. Suitable sites should be selected for pathological examination.

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.

Acute Mast Cell Leukemia Preceded by Malignant Mediastinal Germ Cell Tumor: A Case Report and Literature Review

Background

Case Presentation

Conclusion

How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence

PURPOSE

To present the current evidence and the development of studies in recent years on the management of extragonadal germ cell tumors (EGCT).

METHODS

A systematic literature search was conducted in Medline and the Cochrane Library. Studies within the search period (January 2010 to February 2021) that addressed the classification, diagnosis, prognosis, treatment, and follow-up of extragonadal tumors were included. Risk of bias was assessed and relevant data were extracted in evidence tables.

RESULTS

The systematic search identified nine studies. Germ cell tumors (GCT) arise predominantly from within the testis, but about 5% of the tumors are primarily located extragonadal. EGCT are localized primarily mediastinal or retroperitoneal in the midline of the body. EGCT patients are classified according to the IGCCCG classification. Consecutively, all mediastinal non-seminomatous EGCT patients belong to the "poor prognosis" group. In contrast mediastinal seminoma and both retroperitoneal seminoma and non-seminoma patients seem to have a similar prognosis as patients with gonadal GCTs and metastasis at theses respective sites. The standard chemotherapy regimen for patients with a EGCT consists of 3-4 cycles (good vs intermediate prognosis) of bleomycin, etoposid, cisplatin (BEP); however, due to their very poor prognosis patients with non-seminomatous mediastinal GCT should receive a dose-intensified or high-dose chemotherapy approach upfront on an individual basis and should thus be referred to expert centers Ifosfamide may be exchanged for bleomycin in cases of additional pulmonary metastasis due to subsequently planned resections. In general patients with non-seminomatous EGCT, residual tumor resection (RTR) should be performed after chemotherapy.

CONCLUSION

In general, non-seminomatous EGCT have a poorer prognosis compared to testicular GCT, while seminomatous EGGCT seem to have a similar prognosis to patients with metastatic testicular seminoma. The current insights on EGCT are limited, since all data are mainly based on case series and studies with small patient numbers and non-comparative studies. In general, systemic treatment should be performed like in testicular metastatic GCTs but upfront dose intensification of chemotherapy should be considered for mediastinal non-seminoma patients. Thus, EGCT should be referred to interdisciplinary centers with utmost experience in the treatment of germ cell tumors.

Primary Mediastinal and Testicular Germ Cell Tumors in Adolescents and Adults: A Comparison of Genomic Alterations and Clinical Implications

Simple Summary

The germ cell tumors (GCTs) family is a heterogeneous group of neoplasms that includes tumors affecting testis (TGCTs) and rarer cases occurring in extragonadal sites. Mediastinal germ cell tumors (MGCTs) are more aggressive and have poorer prognosis. Due to their rarity of MGCTs, few molecular and clinical studies are reported. MGCTs share biological similarities with TGCT, and international guidelines recommend use of the same therapies validated for TGCT. However, while high response rate is achieved in TGCT, MGCT tend to be resistant to therapy. This review resumes all molecular findings reported in MGCTs, summarizing molecular characteristics common with TGCT and highlighting the different molecular alterations that characterize mediastinal tumors. A deeper understanding of the MGCT biology will help in clinical management of these patients.

Abstract

Mediastinal germ cell tumors (MGCTs) share histologic, molecular and biomarkers features with testicular GCTs; however, nonseminomatous MGCTs are usually more aggressive and have poorer prognosis than nonseminomatous TGCTs. Most nonseminomatous MGCT cases show early resistance to platinum-based therapies and seldom have been associated with the onset of one or more concomitant somatic malignancies, in particular myeloid neoplasms with recent findings supporting a common, shared genetic precursor with the primary MGCT. Genomic, transcriptomic and epigenetic features of testicular GCTs have been extensively studied, allowing for the understanding of GCT development and transformation of seminomatous and nonseminomatous histologies. However, MGCTs are still lacking proper multi-omics analysis and only few data are reported in the literature. Understanding of the mechanism involved in the development, in the progression and in their higher resistance to common therapies is still poorly understood. With this review, we aim to collect all molecular findings reported in this rare disease, resuming the similarities and disparities with the gonadal counterparts.

Vasculogenic Mesenchymal Tumor: A Clinicopathologic and Molecular Study of 55 Cases of a Distinctive Neoplasm Originating From Mediastinal Yolk Sac Tumor and an Occasional Precursor to Angiosarcoma

We report 55 postchemotherapy resections of primary nonseminomatous mediastinal germ cell tumors with prominent vasculogenic features showing the formation of rudimentary to well-developed neoplastic vessels within primitive mesenchyme. These cases represented 25% of a cohort of 221 such specimens. The patients were 19 to 49 years old (mean, 28 y) and 98% had serological evidence of yolk sac tumor. The vasculogenic lesions, felt to represent a neoplastic reiteration of embryonic vasculogenesis in the splanchnic mesoderm of the yolk sac, were further subdivided into teratoma with vasculogenic stroma (n=9), vasculogenic mesenchymal tumor (VMT) (n=42, further classified into low grade [n=24] and high grade [n=18]), and angiosarcoma (n=4). The distinction of teratoma with vasculogenic stroma from VMT was based solely on the greater extent of VMT (exceeding 1 low power [×4 objective] microscopic field), with both categories showing a spectrum of vessels lined by atypical endothelium in a nonendothelial neoplastic stroma that often also generated vascular walls comprised of atypical smooth muscle. The angiosarcomas showed stratification of highly atypical endothelial cells or anastomosing vessels lined by nonstratified but cytologically similar endothelium. Immunohistochemical studies supported the generation of neoplastic vessels from the tumor stroma, most commonly by the development of stromal clefts showing reactivity for podoplanin, CD34, and occasionally ERG, followed by the gradual development from the clefts of thin-walled vessels that later became encircled by stromal cells showing smooth muscle differentiation by immunohistochemistry. Occasionally, round collections of stromal erythrocytes became surrounded by stromal cells to generate blood vessels. Fluorescence in situ hybridization showed chromosome 12p copy number increase in both the endothelial component and stromal component in 8/9 VMT cases and in 1/1 angiosarcoma. On follow-up, no patient with teratoma with vasculogenic stroma had evidence of a subsequent vascular tumor or sarcoma, whereas 8 of the 35 (23%) patients with VMTs (2 low grade and 6 high grade) and meaningful follow-up developed sarcoma (1 angiosarcoma, 2 rhabdomyosarcomas, and 5 not further characterized). The difference between low-grade and high-grade tumors was of borderline significance (P=0.058). Two of the 4 patients with angiosarcoma died of metastatic angiosarcoma, with the other 2 disease-free at 6.8 and 7 years. Compared with the 165 patients with follow-up and no vasculogenic lesions, there was a highly significant (P=4.3×10-5) association of any vasculogenic lesion with sarcomatoid tumors during the clinical course of VMT patients. In addition, 5/46 patients with follow-up and vasculogenic lesions (11%) died of either leukemia or myelodysplastic syndrome compared with 2 of 166 (1%) lacking them (P=0.0012). Three of the 5 patients had identifiable immature hematopoietic cells within their vasculogenic lesions, but 4 other VMT patients with these did not develop leukemia or myelodysplasia. We conclude: (1) vasculogenic lesions are frequent in postchemotherapy resections of primary mediastinal germ cell tumors with yolk sac tumor components; (2) they mostly consist of neoplastic vessels in a stroma that also generates neoplastic vascular walls of smooth muscle; (3) VMTs are associated with an increased incidence of sarcomas, even though most vasculogenic lesions in this context do not meet criteria for angiosarcoma; (4) the presence of vasculogenic lesions in postchemotherapy resections of primary mediastinal germ cell tumors place patients at increased risk for leukemia or myelodysplasia.

Impact of luteinizing hormone suppression on hematopoietic recovery after intensive chemotherapy in patients with leukemia

Treatment of acute leukemia with intensive chemotherapy leads to an increased risk of myelosuppression. Luteinizing hormone (LH) blockade improves hematopoietic recovery in mice after radiation or chemotherapy, through protection of the hematopoietic stem cells which express the LH receptor. We hypothesized that LH blockade improves hematopoietic recovery following intensive chemotherapy in patients with leukemia. We conducted a retrospective analysis on pre-menopausal women with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) who received intensive chemotherapy and leuprolide given for abnormal uterine bleeding prevention or treatment. Given that leuprolide is more commonly administered in younger patients, we performed propensity score matching between the leuprolide (AML n=64; ALL n=49) and control groups (AML n=128; ALL n=98 patients). Patients with AML who received leuprolide had an additional increase of 13.8x10⁹/L/year in their platelet count, and a 0.19x 10⁹/L/year increase in their lymphocyte count after chemotherapy compared to control (P=0.02; P=0.03 respectively). Those with ALL who received leuprolide had an additional increase of 0.37x10⁹/L/year in their absolute neutrophil count (P=0.02). In AML, leuprolide was associated with higher long-term hemoglobin levels (P<0.001) and less blood transfusions (mean, 23.9 vs. 34.7 units; P=0.002) compared to control. In a multivariate analysis, leuprolide was identified as an independent factor predicting improved hemoglobin levels, lymphocyte and platelet counts in AML. In conclusion, leuprolide use in leukemia patients receiving intensive chemotherapy was associated with improved long-term blood count recovery and with decreased transfusion requirements in AML.

Germ cell tumors and associated hematologic malignancies evolve from a common shared precursor

Germ cell tumors (GCTs) are the most common cancer in men between the ages of 15 and 40. Although most patients are cured, those with disease arising in the mediastinum have distinctly poor outcomes. One in every 17 patients with primary mediastinal nonseminomatous GCTs develop an incurable hematologic malignancy and prior data intriguingly suggest a clonal relationship exists between hematologic malignancies and GCTs in these cases. To date, however, the precise clonal relationship between GCTs and the diverse additional somatic malignancies arising in such individuals have not been determined. Here, we traced the clonal evolution and characterized the genetic features of each neoplasm from a cohort of 15 patients with GCTs and associated hematologic malignancies. We discovered that GCTs and hematologic malignancies developing in such individuals evolved from a common shared precursor, nearly all of which harbored allelically imbalanced p53 and/or RAS pathway mutations. Hematologic malignancies arising in this setting genetically resembled mediastinal GCTs rather than de novo myeloid neoplasms. Our findings argue that this scenario represents a unique clinical syndrome, distinct from de novo GCTs or hematologic malignancies, initiated by an ancestral precursor that gives rise to the parallel evolution of GCTs and blood cancers in these patients.

Acute myeloid leukemia following a primary mediastinal germ cell tumor

Introduction

There is a known association between primary mediastinal germ cell tumor (PMGCT) and hematologic malignancy that is not linked to treatment. They are exceptionally rare entities with a low morbidity and a poor prognosis.

Case presentation

An 11‐year‐old boy presented with an anterior mediastinal mass diagnosed as a malignant germ cell tumor on the basis of an excisional biopsy. He was found to have acute myeloid leukemia (AML) two years after the chemotherapy for his germ cell tumor. The clinical course was very aggressive with a survival time of only 1 week after diagnosis of AML associated with PMGCT.

Conclusion

AML associated with PMGCT needs to be diagnosed correctly. Relevant examinations should be carried out in patients with PMGCTs during and after chemotherapy, and long‐term follow‐up is still necessary to reduce the risk of morbidity and mortality.

TP53 and PTEN mutations were shared in concurrent germ cell tumor and acute megakaryoblastic leukemia

Background

The occurrence of a mediastinal germ cell tumor (GCT) and hematological malignancy in the same patient is very rare. Due to its rarity, there have been only two reports of the concurrent cases undergoing detailed genetic analysis with whole-exome sequencing (WES), and the possible clonal relationship between the both tumors remained not fully elucidated.

Methods

We performed whole-exome sequencing analysis of mediastinal GCT and acute myeloid leukemia (AML) samples obtained from one young Japanese male adult patient with concurrent both tumors, and investigated the possible clonal relationship between them.

Results

Sixteen somatic mutations were detected in the mediastinal GCT sample and 18 somatic mutations in the AML sample. Mutations in nine genes, including TP53 and PTEN both known as tumor suppressor genes, were shared in both tumors.

Conclusions

All in our case and in the previous two cases with concurrent mediastinal GCT and AML undergoing with whole-exome sequencing analysis, TP53 and PTEN mutations were commonly shared in both tumors. These data not only suggest that these tumors share a common founding clone, but also indicate that associated mediastinal GCT and AML harboring TP53 and PTEN mutations represent a unique biological entity.

Management and Long-term Outcomes of Giant Mediastinal Germ Cell Tumors in Children

Purpose: The purpose of the study is to evaluate the outcome of children with giant mediastinal germ cell tumors (GCTs). Materials and Methods: A retrospective study of children diagnosed with GCTs treated at our hospital from 1998 to 2014 was performed. They were evaluated for their tumor size, malignancy, treatment, complications, and outcome. Results: Twelve giant mediastinal GCT patients were included in the study. Age ranged from 7 to 144 months (median 12 months) and all except one were males. The average tumor size was 10.4 cm (range 6 cm × 5 cm–16 cm × 13 cm) and in four patients, they were large enough to occupy nearly the entire hemithorax. Nine children had benign tumors, and these were resected upfront. The remaining three cases with malignant disease received neoadjuvant chemotherapy. No significant reduction in size was noticed in these patients, but alpha-fetoprotein levels decreased in all the three, and they were later resected. Eight (67%) were resected through posterolateral thoracotomy and 4 (33%) through median sternotomy approach. One patient had a dumbbell-shaped thoracoabdominal tumor extending through a Bochdalek hernia. He required additional laparotomy as well as diaphragmatic repair. There were no postoperative complications. The malignant GCTs received total four courses of PEB. All patients were alive and asymptomatic at a mean follow-up of 55.4 months (range 10–146 months). Conclusions: Mediastinal GCTs have bimodal age distribution and show male preponderance. Malignant mediastinal GCTs responded well to neoadjuvant chemotherapy through a reduction in size was not noticed. Complete excision often in coordination with cardiothoracic-vascular surgeons can lead to long-term symptom-free survival even in giant tumors.

Acute Myeloblastic Leukemia Associated with Mediastinal Nonseminomatous Germ Cell Tumors. Report on two Cases

The demonstrated association with hematologic neoplasms may partially account for the poor survival of patients with mediastinal nonseminomatous germ cell tumors (MNSGCT) compared to patients with testicular and retroperitoneal counterparts. It has been shown that the median interval from the diagnosis of MNSGCT to the diagnosis of the hematologic disorders is 6 months, which contrasts sharply with the average time of 2 to 3 years for the development of therapy-related leukemias. The 2 cases herein described, 1 male and 1 female, developed acute M2 leukemia 4 and 2 years after the diagnosis of MNSGCT. In the second patient (the first female ever described), we cannot exclude a pathogenetic role of the PEB regimen (platinum, etoposide, bleomicin), even though the total dose of etoposide administred has been demonstrated to have a mild leukemogenic potential. This is not the case of the first patient, who did not receive adjuvant chemotherapy after the radical resection of primary MNGSCT and developed the hematologic disorder a few months after local recurrence. In conclusion, the time elapsed from chemotherapy administration does not discriminate the hematologic neoplasms associated to MNGSCT from those related to therapy.

Why are hematopoietic stem cells so 'sexy'? on a search for developmental explanation

Evidence has accumulated that normal human and murine hematopoietic stem cells express several functional pituitary and gonadal sex hormones, and that, in fact, some sex hormones, such as androgens, have been employed for many years to stimulate hematopoiesis in patients with bone marrow aplasia. Interestingly, sex hormone receptors are also expressed by leukemic cell lines and blasts. In this review, I will discuss the emerging question of why hematopoietic cells express these receptors. A tempting hypothetical explanation for this phenomenon is that hematopoietic stem cells are related to subpopulation of migrating primordial germ cells. To support of this notion, the anatomical sites of origin of primitive and definitive hematopoiesis during embryonic development are tightly connected with the migratory route of primordial germ cells: from the proximal epiblast to the extraembryonic endoderm at the bottom of the yolk sac and then back to the embryo proper via the primitive streak to the aorta-gonado-mesonephros (AGM) region on the way to the genital ridges. The migration of these cells overlaps with the emergence of primitive hematopoiesis in the blood islands at the bottom of the yolk sac, and definitive hematopoiesis that occurs in hemogenic endothelium in the embryonic dorsal aorta in AGM region.

Non-seminomatous mediastinal germ cell tumor and acute megakaryoblastic leukemia

The association between mediastinal germ cell tumors (MGCT) and acute megakaryoblastic (M7) leukemia has been known for many years. We hereby present this review to better characterize the coexistence of these entities as well as the salient features, the treatment options, and the overall prognosis. A search of PUBMED, Medline, and EMBASE databases via OVID engine for primary articles and case reports under keywords "germ cell tumors" and "acute myeloid leukemia" revealed a total of 26 cases in English that reported MGCT and M7 leukemia. The median age at diagnosis of MGCT was 24 (13-36) years. All cases were stage III. All cases of MGCT were of non-seminomatous origin and one case was unclassified. MGCT occurred prior to the diagnosis of leukemia in 46% of cases and concomitantly in 31% of cases. M7 leukemia was never reported prior to the appearance of MGCT. Complex cytogenetics and hyperdiploidy were the most commonly reported cytogenetic abnormalities. In the 23 cases where the treatment regimen was available, platinum-based chemotherapy directed towards management of the germ cell tumors was used initially in 21 cases and leukemia-directed treatment was used initially in 2 cases only. The median time from diagnosis of MGCT to development of M7 leukemia was 5 (2.25-39) months. Median time to death from the initial diagnosis of MGCT was 6 (0.5-60) months. Patients with a history of MGCT are at higher risk of developing M7 leukemia. They need long-term follow-up with a particular attention to the development of hematological malignancies. The overall prognosis remains poor.

Long-term outcomes of pediatric and adolescent mediastinal germ cell tumors: a single pediatric oncology institutional experience

PURPOSE

To evaluate the epidemiologic, demographic, and clinical characteristics, as well as prognostic factors and long-term outcomes of mediastinal germ cell tumors (MGCT) in children.

PATIENTS AND METHODS

A retrospective study of pediatric patients diagnosed with a primary MGCT between January 1963 and August of 2014 was performed.

RESULTS

Twenty-five patients were identified. Six children with teratomas were treated with resection alone (median age 7.8 years, range newborn to 15 years) and were cured without recurrence or progression. Nineteen children were treated for a malignant MGCT (median age 11.7 years, range 7 months-18 years); 5 year overall survival (OS) was 0.39 ± 0.12. For malignant non-seminomatous mediastinal germ cell tumors, platinum-based chemotherapy regimen (OS 0.56 vs 0.14, p = 0.03), complete surgical resection with negative margins (OS 0.73 vs 0.11, p = 0.03); and localized disease (OS 0.76 vs 0.0, p = 0.004) demonstrated a survival advantage.

CONCLUSIONS

Initial surgical resection is appropriate for teratomas. Localized disease, complete resection, and platinum-based chemotherapy are associated with improved survival in malignant non-seminomatous mediastinal germ cell tumors. Neoadjuvant, platinum-based three drug regimens followed by delayed surgical resection is the appropriate treatment modality for malignant mediastinal germ cell tumors.

A common founding clone with TP53 and PTEN mutations gives rise to a concurrent germ cell tumor and acute megakaryoblastic leukemia

We report the findings from a patient who presented with a concurrent mediastinal germ cell tumor (GCT) and acute myeloid leukemia (AML). Bone marrow pathology was consistent with a diagnosis of acute megakaryoblastic leukemia (AML M7), and biopsy of an anterior mediastinal mass was consistent with a nonseminomatous GCT. Prior studies have described associations between hematological malignancies, including AML M7 and nonseminomatous GCTs, and it was recently suggested that a common founding clone initiated both cancers. We performed enhanced exome sequencing on the GCT and the AML M7 from our patient to define the clonal relationship between the two cancers. We found that both samples contained somatic mutations in PTEN (C136R missense) and TP53 (R213 frameshift). The mutations in PTEN and TP53 were present at ∼100% variant allele frequency (VAF) in both tumors. In addition, we detected and validated five other shared somatic mutations. The copy-number analysis of the AML exome data revealed an amplification of Chromosome 12p. We also identified a heterozygous germline variant in FANCA (S858R), which is known to be associated with Fanconi anemia but is of uncertain significance here. In summary, our data not only support a common founding clone for these cancers but also suggest that a specific set of distinct genomic alterations (in PTEN and TP53) underlies the rare association between GCT and AML. This association is likely linked to the treatment resistance and extremely poor outcome of these patients. We cannot resolve the clonal evolution of these tumors given limitations of our data.

Mediastinal Germ Cell Tumor-associated Histiocytic Proliferations Treated With Thalidomide Plus Chemotherapy Followed by Alemtuzumab-containing Reduced Intensity Allogeneic Peripheral Blood Stem Cell Transplantation: A Case Report

Mediastinal nonseminomatous germ cell tumor (MNSGCT)-associated histiocytic proliferations are rare and rapidly fatal disorders. Standard treatment modalities have yet to be established.We report a case of MNSGCT-associated hemophagocytic syndrome that evolved into malignant histiocytosis/disseminated histiocytic sarcoma (MH/HS), which was initially treated with intravenous immunoglobulin, corticosteroids, and cyclosporine. Then, thalidomide plus cyclophosphamide, adriamycin, oncovin, prednisolone chemotherapy followed by alemtuzumab-containing reduced-intensity allogeneic peripheral blood stem cell transplantation (PBSCT) was used as salvage therapy.The severe constitutional symptoms and pancytopenia resolved shortly after thalidomide with cyclophosphamide, adriamycin, oncovin, prednisolone. After PBSCT, the patient developed steroid-dependent skin graft-versus-host disease, but maintained a functional life for 1.5 years. Rapid resolution of chronic graft-versus-host disease preceded the fulminant recurrence of hemophagocytic syndrome and MH/HS.Thalidomide plus chemotherapy followed by alemtuzumab-containing reduced intensity allogeneic PBSCT is effective in allaying MNSGCT-associated histiocytic disorders, but does not prevent eventual relapse. However, further posttransplant immune modulation should be developed to completely eradicate the residual MH/HS cells.

Human haematopoietic stem/progenitor cells express several functional sex hormone receptors

Evidence has accumulated that murine haematopoietic stem/progenitor cells (HSPCs) share several markers with the germline, a connection supported by recent reports that pituitary and gonadal sex hormones (SexHs) regulate development of murine HSPCs. It has also been reported that human HSPCs, like their murine counterparts, respond to certain SexHs (e.g. androgens). However, to better address the effects of SexHs, particularly pituitary SexHs, on human haematopoiesis, we tested for expression of receptors for pituitary SexHs, including follicle‐stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL), as well as the receptors for gonadal SexHs, including progesterone, oestrogens, and androgen, on HSPCs purified from human umbilical cord blood (UCB) and peripheral blood (PB). We then tested the functionality of these receptors in ex vivo signal transduction studies and in vitro clonogenic assays. In parallel, we tested the effect of SexHs on human mesenchymal stromal cells (MSCs). Finally, based on our observation that at least some of the UCB‐derived, CD45⁻ very small embryonic‐like stem cells (VSELs) become specified into CD45⁺HSPCs, we also evaluated the expression of pituitary and gonadal SexH receptors on these cells. We report for the first time that human HSPCs and VSELs, like their murine counterparts, express pituitary and gonadal SexH receptors at the mRNA and protein levels. Most importantly, SexH if added to suboptimal doses of haematopoietic cytokines and growth factors enhance clonogenic growth of human HSPCs as well as directly stimulate proliferation of MSCs.

Hematopoietic stem/progenitor cells express several functional sex hormone receptors-novel evidence for a potential developmental link between hematopoiesis and primordial germ cells

Evidence has accumulated that hematopoietic stem progenitor cells (HSPCs) share several markers with the germline, a connection supported by reports that prolactin, androgens, and estrogens stimulate hematopoiesis. To address this issue more directly, we tested the expression of receptors for pituitary-derived hormones, such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH), on purified murine bone marrow (BM) cells enriched for HSPCs and tested the functionality of these receptors in ex vivo signal transduction studies and in vitro clonogenic assays. We also tested whether administration of pituitary- and gonad-derived sex hormones (SexHs) increases incorporation of bromodeoxyuridine (BrdU) into HSPCs and expansion of hematopoietic clonogenic progenitors in mice and promotes recovery of blood counts in sublethally irradiated animals. We report for the first time that HSPCs express functional FSH and LH receptors and that both proliferate in vivo and in vitro in response to stimulation by pituitary SexHs. Furthermore, based on our observations that at least some of CD45(-) very small embryonic-like stem cells (VSELs) may become specified into CD45(+) HSPCs, we also evaluated the expression of pituitary and gonadal SexHs receptors on these cells and tested whether these quiescent cells may expand in vivo in response to SexHs administration. We found that VSELs express SexHs receptors and respond in vivo to SexHs stimulation, as evidenced by BrdU accumulation. Since at least some VSELs share several markers characteristic of migrating primordial germ cells and can be specified into HSPCs, this observation sheds new light on the BM stem cell hierarchy.

A novel view of the adult bone marrow stem cell hierarchy and stem cell trafficking

This review presents a novel view and working hypothesis about the hierarchy within the adult bone marrow stem cell compartment and the still-intriguing question of whether adult bone marrow contains primitive stem cells from early embryonic development, such as cells derived from the epiblast, migrating primordial germ cells or yolk sac-derived hemangioblasts. It also presents a novel view of the mechanisms that govern stem cell mobilization and homing, with special emphasis on the role of the complement cascade as a trigger for egress of hematopoietic stem cells from bone marrow into blood as well as the emerging role of novel homing factors and priming mechanisms that support stromal-derived factor 1-mediated homing of hematopoietic stem/progenitor cells after transplantation.

Expression of the erythropoietin receptor by germline-derived cells - further support for a potential developmental link between the germline and hematopoiesis

BACKGROUND

Expressing several markers of migrating primordial germ cells (PGCs), the rare population of quiescent, bone marrow (BM)-residing very small embryonic-like stem cells (VSELs) can be specified like PGCs into hematopoietic stem/progenitor cells (HSPCs). These two properties of VSELs support the possibility of a developmental origin of HSPCs from migrating PGCs.

METHODS

To address a potential link between VSELs and germ line cells we analyzed by RT-PCR and FACS expression of erythropoietin receptor (EpoR) on murine bone marrow- and human umbilical cord blood-derived VSELs, murine and human teratocarcinoma cell lines and human ovarian cancer cells. A proper gating strategy and immunostaining excluded from FACS analysis potential contamination by erythroblasts. Furthermore, the transwell chemotaxis assays as well as adhesion and signaling studies were performed to demonstrate functionality of erythropoietin - EpoR axes on these cells.

RESULTS

We report here that murine and human VSELs as well as murine and human teratocarcinoma cell lines and ovarian cancer cell lines share a functional EpoR.

CONCLUSIONS

Our data provide more evidence of a potential developmental link between germline cells, VSELs, and HSCs and sheds more light on the developmental hierarchy of the stem cell compartment in adult tissues.

Acquired isochromosome 12p, somatic TP53 and PTEN mutations, and a germline ATM variant in an adolescent male with concurrent acute megakaryoblastic leukemia and mediastinal germ cell tumor

Previous reports have described an association between hematologic malignancies (HMs) and extragonadal germ cell tumor (GCT). Most patients have been adolescent males with mediastinal nonseminomatous GCT. Although a variety of HMs have been reported, there is a striking predilection toward acute megakaryoblastic leukemia (AMKL). Shared cytogenetic anomalies--particularly isochromosome 12p [i(12p)]--have suggested common clonal origins to the tumors. We report the case of a 17-year-old boy presenting with AMKL and a synchronous mediastinal GCT, with the characteristic i(12p) in both neoplasms. The common clonal origin of the AMKL and GCT was further confirmed with massively parallel sequencing, which identified somatic TP53 and PTEN mutations, as well as a rare germline ATM variant. Although these represent commonly mutated genes in cancer, this combination of mutations is not typically associated with either GCT or AMKL, suggesting that these tumors may represent unique biologic entities when they co-occur.

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.

Malignant phyllodes tumor and acute megakaryoblastic leukemia sharing a common clonal origin

There is a well-known association in male patients between mediastinal germ cell tumors (GCT) and hematologic malignancies, with a propensity towards acute megakaryoblastic leukemia. These rare malignancies have been shown to share a common clonal origin, often deduced from the finding of isochromosome 12p, i(12p), in cells from both the solid tumor and the leukemia, and thus are now known to represent different manifestations of the same clonal process. We treated a young female patient with a malignant phyllodes tumor followed by an acute megakaryoblastic leukemia and found several of the same marker chromosomes by karyotype analysis of cells from both the tumor and the leukemia implying a common clonal origin of the two. To the best of our knowledge, this has not been demonstrated in phyllodes tumors before, but indicates that the same type of leukemization may occur of this tumor as has been described in mediastinal GCT.

Malignant transformations in a patient with a mediastinal germ cell tumour: lack of efficacy of bone marrow transplantation after chemotherapy on tumour recurrence

The report describes the case of a young male with a malignant teratoma which was followed by an acute megakaryoblastic leukaemia sharing similar chromosomal abnormalities. In leukemic cells, the authors have obtained cytogenetic evidence by fluorescent in situ hybridisation technique suggesting that this leukaemia arose directly from the germ cell tumour (GCT). The patient received allogenic bone marrow transplantation, which unfortunately, did not prevent the patient to relapse with an undifferentiated sarcoma containing rhabdomyosarcoma components, as well as reappearance of a residual teratoma with metastasis. The treatment strategy for malignant transformation of a GCT seems to be unpredictable and should be dictated by the malignant tissue counterpart. Except for acute leukaemia, unresectable or metastatic settings will generally require multi-modal therapy including chemotherapy, in addition to loco regional approaches. Additionally, long or even a life time follow-up is necessary in patients with poor prognostic characteristics.

Development of acute megakaryoblastic leukemia with isochromosome (12p) after a primary mediastinal germ cell tumor in Korea

The association of hematological malignancies with a mediastinal germ cell tumor (GCT) is very rare. We report one case of a young adult male with primary mediastinal GCT who subsequently developed acute megakaryoblastic leukemia involving isochromosome (12p). A 25-yr-old man had been diagnosed with a mediastinal GCT and underwent surgical resection and adjuvant chemotherapy. At 1 week after the last cycle of chemotherapy, his peripheral blood showed leukocytosis with blasts. A bone marrow study confirmed the acute megakaryoblastic leukemia. A cytogenetic study revealed a complex karyotype with i(12p). Although additional chemotherapy was administered, the patient could not attain remission and died of septic shock. This case was definitely distinct from therapy-related secondary leukemia in terms of clinical, morphologic, and cytogenetic features. To our knowledge, this is the first case report of a patient with mediastinal GCT subsequently developing acute megakaryoblastic leukemia involving i(12p) in Korea.

Late complications of chemotherapy in testicular cancer

Cisplatin-based treatment has significantly increased survival in testicular cancer patients. Therefore, there has been enough interest for the late toxic effects of chemotherapy which affect the quality of life of the cancer survivors. These toxic effects may either persist or present long after the end of chemotherapy and involve the impairment of renal function, neurotoxicity, pulmonary toxicity and vascular disease. Also, a major issue experienced by a large number of patients is infertility, which has been improved due to modified surgical techniques, reduced treatment intensity, the use of sperm cryopreservation and methods of assisted reproduction. Physicians should also be aware of the risk of secondary malignancy development. Therefore, close follow-up of the testicular cancer survivors as well as, focus on minimizing treatment complications through improvement of treatment strategies are warranted.

The challenge of poor-prognosis germ cell tumors

Patients who have a poor prognosis can be identified at presentation by well-defined prognostic factors. Prognostic groups as defined by the International Germ Cell Consensus Classification should be used in the clinic, in clinical trials, and when reporting results. No systemic treatment has been shown to improve outcome compared with four cycles of chemotherapy composed of bleomycin, etoposide, and cisplatin, which remains the standard of care. Surgery to resect residual masses after chemotherapy and in the salvage setting is a vital component of optimal care. The best outcomes occur with treatment at a center with experience and expertise in their management. Further major improvements are likely to require novel systemic therapies rather than modifications of existing approaches.

Non-seminomatous germ-cell tumour associated with acute megakaryoblastic leukaemia

The association of mediastinal germ-cell tumours (MGCTs) with haematologic neoplasms is a rare though well known circumstance, and few cases are found in the literature. Most of these refer to non-seminomatous tumours in young males. The diagnosis of the haematological condition is usually either synchronic or metachronic with that of the germ-cell tumour. From those cases that have been published, we know that the prognosis is poor and basically determined by the haematologic neoplasia. The case report we present is that of a young male with an initial diagnosis of both conditions. It was possible to apply specific treatment, initially in the case of the leukaemia, and later in the case of the germ-cell tumour. The approach adopted is a multidisciplinary one.

Pluripotent stem cells and their niches

The ability of stem cells to self-renew and to replace mature cells is fundamental to ontogeny and tissue regeneration. Stem cells of the adult organism can be categorized as mono-, bi-, or multipotent, based on the number of mature cell types to which they can give rise. In contrast, pluripotent stem cells of the early embryo have the ability to form every cell type of the adult body. Permanent lines of pluripotent stem cells have been derived from preimplantation embryos (embryonic stem cells), fetal primordial germ cells (embryonic germ cells), and malignant teratocarcinomas (embryonal carcinoma cells). Cultured pluripotent stem cells can easily be manipulated genetically, and they can be matured into adult-type stem cells and terminally differentiated cell types in vitro, thereby, providing powerful model systems for the study of mammalian embryogenesis and disease processes. In addition, human embryonic stem cell lines hold great promise for the development of novel regenerative therapies. To fully utilize the potential of these cells, we must first understand the mechanisms that control pluripotent stem cell fate and function. In recent decades, the microenvironment or niche has emerged as particularly critical for stem cell regulation. In this article, we review how pluripotent stem cell signal transduction mechanisms and transcription factor circuitries integrate information provided by the microenvironment. In addition, we consider the potential existence and location of adult pluripotent stem cell niches, based on the notion that a revealing feature indicating the presence of stem cells in a given tissue is the occurrence of tumors whose characteristics reflect the normal developmental potential of the cognate stem cells.

True malignant histiocytosis with trisomy 9 following primary mediastinal germ cell tumor

A 24-year-old Japanese man was admitted due to bloody phlegm in May 2002. A diagnosis of mediastinal germ cell tumor, mixed type involving seminoma, immature teratoma and embryonal carcinoma, was made by transthoracic needle biopsy. Three months later, his complete blood counts revealed pancytopenia with high fever. Examination of bone marrow revealed increased atypical large histiocytes (5.6%) with hemophagocytosis, and thus, hemophagocytic syndrome related to germ cell tumor was diagnosed. In addition, chromosomal analysis of the bone marrow cells revealed a 47, XY, +9 genotype. Chemotherapies for germ cell tumor and hemophagocytic syndrome were performed without any improvement, and he died of diffuse alveolar damage. Autopsy revealed diffuse infiltration of immature histiocytes with hemophagocytosis in the liver, spleen and bone marrow. The atypical histiocytes were positive for CD68 and lysozyme and negative for lymphoid markers, and the diagnosis of true malignant histiocytosis associated with mediastinal germ cell tumor was made. The rare chromosomal abnormality of trisomy 9, a marker for benzene-related leukemia, was seen in the present case without apparent benzene exposure.

Tumors of the mediastinum

Tumors of the mediastinum represent a wide diversity of disease states. The location and composition of a mass is critical to narrowing the differential diagnosis. The most common causes of an anterior mediastinal mass include the following: thymoma; teratoma; thyroid disease; and lymphoma. Masses of the middle mediastinum are typically congenital cysts, including foregut and pericardial cysts, while those that arise in the posterior mediastinum are often neurogenic tumors. The clinical sequelae of mediastinal masses can range from being asymptomatic to producing symptoms of cough, chest pain, and dyspnea. This article will review the anatomy of the mediastinum as well as the different clinical, radiographic, and prognostic features, and therapeutic options of the most commonly encountered masses.