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

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

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.

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

Background

Case Presentation

Conclusion

Mediastinal germ cell tumors: a narrative review of their traits and aggressiveness features

OBJECTIVE

Mediastinal extragonadal germ-cell tumors (MEGCTs) are rare neoplasms with a multifaceted clinical behavior. This paper is devoted to review their main characteristics, including histological patterns and different factors of aggressiveness in MEGCTs. Proper understanding of the latter can help to better stratify patients' prognoses and improve clinical management.

BACKGROUND

Different theories exist on the origin of MEGCTs, including primordial germ cells deposition during embryogenesis. MEGCTs predominantly affects young males and aggressiveness follows the ability of local and systemic spread of each germ-cell neoplasia subtype, as well as their distinct responsiveness to therapy. Indeed, non-seminomatous MEGCTs have a worse prognosis. Unfortunately, they are also more frequent than seminomas in the mediastinum. Regardless of histological type, local aggressiveness can follow tumoral expansion with compression on or infiltration of mediastinal structures. Chemotherapy can be effective in reducing neoplastic volume, but different levels of sensitivity can be found in different MGCTs. In particular, a chemo-resistant teratoma component of a mixed MEGCTs can undergo a paradoxical enlargement after chemotherapy, while other components of the tumor regress. This is reflected by a concomitant normalization of serum tumoral markers and cardiopulmonary deterioration due to compression. Such clinical phenomenon, called growing-teratoma syndrome (GTS), requires a prompt surgical approach.

METHODS

A literature research of pertinent epidemiological, pathological and clinical articles was conducted.

CONCLUSION

The mediastinum can harbor different kinds of neoplasia, including GCTs. The full spectrum of MEGCTs includes a variety of tumors with different clinical behaviors. Aggressiveness follows the inherent ability of local and systemic spread of each neoplastic type, as well as their distinct responsiveness to therapy.

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.

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.

Whole genome, exon mutation and transcriptomic profiling of acute myeloid leukemia: A case report

The present study aimed to observe previously unidentified gene mutation and expression profiles associated with acute myeloid leukemia (AML) at the individual level, based on the blood samples of a father-son pair. Genomic DNA and RNA samples from blood serum were collected. Whole-genome sequencing (WGS) and whole-exome sequencing (WES), as well as mRNA sequencing of the son, were performed. For the father's sample, a total of 3,897,164 single nucleotide polymorphisms (SNPs) and 780,834 insertion and deletions (indels) were identified. Regarding amino acid translation, there were 11,316 non-synonymous, 12 stop-loss, 12,033 synonymous, 92 stop-gain SNPs, 63 frameshift insertions, 73 frameshift deletions, 242 non-frameshift insertions, 248 non-frameshift deletions, four stop-gains and two stop-loss for indel variants. Among the AML-related genes that had been previously identified, 14 genes were found in the father's exon region. For WES of the son's DNA, 96,639 SNPs were identified, including 10,504 non-synonymous SNPs. Seven mutant genes were found in sons' exon region compared with 121 AML-related genes. Based on the transcriptomic sequencing, there were 54 differentially expressed mRNAs, including 31 upregulated and 23 downregulated mRNAs. In the exon region, 10,072 SNPs were detected, and different types of alternative splicing in the son's sample were observed. Overall, whole genome, exon mutation and transcriptomic profiling of the present two patients with AML may provide a new insight into the molecular events governing the development of 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.

Mediastinal Germ Cell Tumor and Acute Megakaryoblastic Leukemia With Co-occurring KRAS Mutation and Complex Cytogenetics

Young males have a unique but rare predilection to develop mediastinal nonseminomatous germ cell tumors (NSGCTs) and concomitant acute megakaryoblastic leukemia (AMKL). Common cytogenetic and molecular abnormalities such as isochromosome 12p and somatic Tumor Protein P53(TP53) and Phosphatase And Tensin Homolog (PTEN) mutations have been reported in the presumed mutual neoplastic clones of origin. We report the case of a 17-year-old male who presented with a mediastinal NSGCT with high-grade sarcomatous transformation and a diagnosis of AMKL approximately 4 months later. Next-generation sequencing revealed identical KRAS Proto-Oncogene, GTPase (KRAS) p.Ala146Thr, TP53 p.Leu257Pro, and PTEN p.Leu181Pro missense mutations at similar variant allele frequencies in both the NSGCT and AMKL samples. Cytogenetic and microarray analyses detected shared copy gains in all chromosomes except chromosomes 9, 13, and Y. Multiple additional clonal chromosomal alterations were detected in the AMKL sample when compared with the NSGCT. This case emphasizes the shared clonal origins of these malignancies and identifies KRAS and other copy number alterations as potential molecular drivers in a subset of these combined diseases.

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.

Pediatric mediastinal germ cell tumors

Mediastinal germ cell tumors (GCTs) are a rare and heterogeneous group of neoplasms. Although histologically resembling their gonadal counterparts, they differ considerably in their clinical characteristics, biological behavior and prognostic outcome. The rarity of mediastinal GCTs has hindered their meaningful analysis, with most studies and clinical trials including them along with other extragonadal GCTs, which has led to a lack of consensus on optimal treatment strategies, and a lull in improvement in patient outcomes. Diagnosis of mediastinal GCT requires a multipronged approach, and encompasses multidisciplinary treatment including chemotherapy followed by surgery, with or without radiotherapy. In view of sustained response rates to current management protocols, the focus needs to be shifted to identifying patients in whom treatment regimens can be downscaled with the aim of decreasing long term morbidity and improving quality of life in low risk patient groups, while improving survival rates in poor risk patient subsets. In this scenario, better understanding of the molecular pathogenesis of these tumors may lead to identification of novel biomarkers and therapeutic targets, as well as improved disease segmentation and risk stratification, thus helping to avoid the toxicity and morbidity associated with current one-fits-all treatment strategies. Multi-institutional collaborations across continents are necessary to generate meaningful data, and are the face of future developments in this arena.

Pediatric Acute Megakaryoblastic Leukemia: Multitasking Fusion Proteins and Oncogenic Cooperations

Pediatric leukemia presents specific clinical and genetic features from adult leukemia but the underpinning mechanisms of transformation are still unclear. Acute megakaryoblastic leukemia (AMKL) is the malignant accumulation of progenitors of the megakaryocyte lineage that normally produce blood platelets. AMKL is diagnosed de novo, in patients showing a poor prognosis, or in Down syndrome (DS) patients with a better prognosis. Recent data show that de novo AMKL is primarily associated with chromosomal alterations leading to the expression of fusions between transcriptional regulators. This review highlights the most recurrent genetic events found in de novo pediatric AMKL patients and, based on recent functional analyses, proposes a mechanism of leukemogenesis common to de novo and DS-AMKL.

A variant c-KIT mutation, D816H, fundamental to the sequential development of an ovarian mixed germ cell tumor and systemic mastocytosis with chronic myelomonocytic leukemia

An activating point mutation of the c-KIT tyrosine kinase receptor gene, D816H, has been described in germ cell tumors (GCTs). We report an adolescent diagnosed with an ovarian mixed GCT and systemic mastocytosis with chronic myelomonocytic leukemia (SM-CMML). The teratoma and dysgerminoma differed by copy number aberrations via single nucleotide polymorphism (SNP) microarray, but were inclusive of the same c-KIT D816H point mutation (c.2446G>C) also identified in blood and bone marrow mast cells. These findings indicate not only a clonal origin of the GCT and hematologic malignancy, but also suggest a rare KIT mutation may be playing a fundamental role in malignancy development.

Acute Leukemia and Concurrent Mediastinal Germ Cell Tumor: Case Report and Literature Review

There is a known association of primary nonseminomatous mediastinal germ cell tumors (NSMGCT) and hematologic malignancy in younger males not linked to treatment. When combined these two rare entities convey a very poor prognosis. Here we report a 16-year-old male with an anterior mediastinal mass diagnosed as a malignant germ cell tumor based on elevation of serologic markers. He was found to have acute leukemia with megakaryocytic differentiation several days later. We focus our report on the pathologic findings, including a review of the literature, and a novel molecular analysis of the germ cell tumor.

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.

Functional and genetic screening of acute myeloid leukemia associated with mediastinal germ cell tumor identifies MEK inhibitor as an active clinical agent

Background

Hematologic malignancies arising in the setting of established germ cell tumors have been previously described and have a dismal prognosis. Identification of targetable mutations and pathway dysregulation through massively parallel sequencing and functional assays provides new approaches to disease management.

Case Presentation

Herein, we report the case of a 23-year-old male who was diagnosed with a mediastinal germ cell tumor and subsequent acute myeloid leukemia. A shared clonal origin was demonstrated through identification of identical NRAS and TP53 somatic mutations in both malignancies. The patient’s leukemia was refractory to standard therapies with short interval relapse. Functional assays demonstrated the patient’s blasts to be sensitive to the mitogen-activated protein kinase kinase (MEK) inhibitor trametinib, correlating with the activating NRAS mutation. The patient experienced a sustained partial remission while on trametinib therapy but ultimately suffered relapse of the germ cell tumor. The leukemic clone remained stable and sensitive to trametinib at that time.

Conclusions

This case highlights the potential power of combining genetic sequencing and in vitro functional assays with targeted therapies in the treatment of rare diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0258-1) contains supplementary material, which is available to authorized users.

Mixed Phenotype Acute Leukemia with Low Hypodiploidy in a Pediatric Patient

We describe the case of a 16 year-old female with mixed phenotype acute leukemia B/myeloid, NOS (formerly biphenotypic leukemia) with masked hypodiploidy and somatic TP53 and CDKN2A/B deletions. She achieved morphologic remission with lymphoid-directed multi-agent chemotherapy, but experienced an early medullary relapse 11 months from initial diagnosis. Her case details the unusual finding of hypodiploidy in a patient with ambiguous lineage leukemia and highlights the complexity of therapy selection for these high-risk patients.