Post-chemotherapy maturation in supratentorial primitive neuroectodermal tumors

Embryonal tumor with multilayered rosettes: Post-treatment maturation and implications for future therapy

BACKGROUND

Embryonal tumor with multilayered rosettes (ETMR) is a deadly grade IV pediatric brain tumor. Despite an intensive multimodal treatment approach that includes surgical resection, high-dose chemotherapy, and radiotherapy, the progression-free survival at 5 years is less than 30%.

CASE

We report a case of long-term survival in a 5-month old female with a large mass in the posterior fossa, diagnosed as ETMR, which subsequently underwent treatment-induced maturation. Prior to chemotherapy, histopathology revealed an abundance of highly proliferative, undifferentiated cells and multilayered rosette structures. Conversely, post-treatment histopathology revealed cell populations that differentiated into neuronal and ganglionic phenotypes. At 5-year follow-up, the patient remains progression-free.

CONCLUSION

This finding contributes to the few reports to date of post-treatment differentiation/maturation of ETMR cell populations, with an implication for less cytotoxic therapeutic interventions aimed at differentiation.

Postchemotherapy gross residual tumor in non-high-risk neuroblastoma: Clinical significance and the role of adjuvant therapy

BACKGROUND

Although survival rate among patients with non-high-risk neuroblastoma is excellent, a gross residual tumor (GRT) is often present at the end of treatment. However, reliable data do not exist on the relevance of a GRT for the risk of progression and the role of adjuvant therapy for patients with GRT.

METHODS

A retrospective review of 131 patients with non-high-risk neuroblastoma who underwent chemotherapy was performed. GRT was defined as >1 cm³ residual soft tissue density on end-of-chemotherapy scans. Progression-free survival (PFS) and overall survival (OS) rates were compared between patients with GRT and those without GRT. A proportional hazards model was also used to assess the effects of GRT and adjuvant therapies, including radiation and isotretinoin therapy on outcomes.

RESULTS

GRT was found in 52 (40%) patients in the study cohort. Correlation was not found between GRT and outcomes (PFS; p = .954, OS; p = .222). In multivariable analysis, GRT remained a nonsignificant predictor of outcome after adjusting for confounders. Local radiation and isotretinoin therapy did not affect outcome for patients with GRT. However, within GRT subgroups, the degree of volume reduction, as well as absolute residual volume in the primary tumor after induction treatment, were significantly associated with outcomes.

CONCLUSION

GRT in non-high-risk neuroblastoma may not indicate active disease that requires additional treatment. However, risk of progression is increased in patients with GRT whose response to treatment was less prominent, thus adjuvant therapy should be reserved only for those patients.

Embryonal tumors with multilayered rosettes, C19MC-altered or not elsewhere classified: Clinicopathological characteristics, prognostic factors, and outcomes of 17 children from 2018 to 2022

Objective

Embryonal tumors with multilayered rosettes (ETMRs) are a histologically heterogeneous entity and gather embryonal tumors with abundant neuropil and true rosettes (ETANTRs), ependymoblastoma, and medulloepithelioma. ETMRs are highly aggressive and associated with poorer clinical courses. However, cases of this entity are rare, and advances in molecular genetics and therapy are minor. The purpose of our study was to retrospectively analyze the clinical, pathological features, and prognostic factors of ETMRs.

Methods

Our cohort consisted of 17 patients diagnosed with ETMRs in our hospital from 2018 to 2022, and two of them were lost to follow-up. Clinical data were retrieved, and immunohistochemistry and genetic analyses were performed.

Results

Among 17 cases, 16 were ETANTRs, and one was medulloepithelioma. Morphologically, tumor cells of ETANTRs could transform into anaplasia and lose the biphasic architecture during tumor progression. Immunohistochemistry of LIN28A revealed positive expression in 17 cases, and the expression of LIN28A was more intense and diffuse in the recurrent lesions than in primaries. The increased N-MYC copy numbers were detected in the primary tumor and recurrence of patient 8. Moreover, the incidence of metastatic disease was 100% in patients aged > 4 years and 18% in the younger group. For patients receiving chemotherapy, the median overall survival time was 7.4 months, while that of those who didn’t receive it was 1.2 months. Nevertheless, surgical approaches, radiotherapy, age at presentation, gender, tumor location, and metastatic status were not associated with independent prognosis.

Conclusion

ETANTR might not present as the typical morphologies during tumor progression, so analyses of C19MC amplification and Lin28A antibody are indispensable for diagnosing ETMRs accurately. Children aged > 4 years tend to have a higher rate of metastasis in ETMRs. Chemotherapy is the only prognostic factor for ETMRs patients with a favorable prognosis. The biological nature and clinical patterns for recurrent diseases need to be further demonstrated to predict prognosis and guide treatment.

Prognostic impact of the multimodal treatment approach in patients with C19MC-altered embryonal tumor with multilayered rosettes

OBJECTIVE

Embryonal tumor with multilayered rosettes (ETMR) is one of the childhood central nervous system tumors with the poorest prognosis; thus, establishing an optimal treatment strategy is essential, However, because of the low incidence and molecular heterogeneity of the tumor, the optimal treatment has not yet been determined. In this study the authors evaluated the prognostic impact of a multimodal treatment approach in patients with ETMR.

METHODS

The authors evaluated 4 patients with ETMR at their institution who showed varied clinical features and also conducted clinical characterization and prognostic analysis of previously reported cases of the ETMR-presenting locus 19q13.42 with a chromosome 19 microRNA cluster (C19MC) amplification, which is known to be a diagnostic hallmark of the tumor.

RESULTS

Of the 4 patients with ETMR in the authors' institution, in 1 case the patient's tumor showed a neuroblastoma-like appearance without multilayered rosettes; however, the diagnosis was confirmed by the presence of amplified C19MC. From a clinical standpoint, 2 patients who underwent gross-total resection (GTR) of the tumor and chemotherapy followed by high-dose chemotherapy (HDC) had long-term complete remission with or without local irradiation. In the multivariate analysis of 43 cases with C19MC-altered ETMR reported in the literature, HDC and local irradiation were significantly correlated with better event-free survival (HR 0.17, p = 0.0087; HR 0.17, p = 0.010) and overall survival (OS) (HR 0.29, p = 0.023; HR 0.28, p = 0.019), respectively. GTR was also correlated with better OS (HR 0.40, p = 0.039).

CONCLUSIONS

This case series demonstrated pathological and clinical heterogeneity among ETMR cases and the diagnostic importance of the molecular genetic approach among embryonal tumors, particularly during infancy. Based on the results of the analysis of molecularly uniformed ETMR cases, multimodal treatment may play a significant role in the prognosis of these tumors.

Clinicopathological characteristics and outcomes in embryonal tumor with multilayered rosettes: A decade long experience from a tertiary care centre in North India

BACKGROUND

Embryonal tumor with multilayered rosettes (ETMR) are a heterogenous group clinically, pathologically and topographically. Due to limited cases, data regarding its molecular genetics, pathology and prognostic factors is evolving. We retrospectively analysed our cohort of ETMR over last decade in order to study their clinicopathological characteristics and outcome.

METHODS

Our cohort consisted of patients diagnosed with Embryonal tumor with abundant neuropil and true rosettes (ETANTR)/Ependymoblastoma (EBL)/ Medulloepithelioma (MEPL) over the past decade. Clinical details, including outcome and imaging data was retrieved. Histological analysis including immunohistochemical work-up was performed.

RESULTS

Cohort included 15 patients with age range between 1 and 28 years and M:F ratio of 1.5:1. Supratentorial location predominated in comparison to tumors arising in posterior fossa. ETANTR and EBL patterns were equally distributed (40% each), followed by one case each of mixed pattern (EBL + ETANTR), MEPL and embryonal tumor, unclassified. All tumors readily expressed LIN 28A and INI-1 was retained. Recurrence with evidence of glial and rhabdoid differentiation was noted in a single patient 9 months following resection. Follow-up period ranged from 1 to 31 months, with overall median survival of 6.4 months. Eight patients were planned for adjuvant treatment following surgery, of which only four could complete it. All patients, except for one, succumbed to the disease.

CONCLUSIONS

ETMR have a heterogenous morphology and gathers ETANTR, EBL, MEPL within its spectrum. Following treatment, the recurrent tumor may feature glial/rhabdoid differentiation. LIN28A is expressed in all cases, however should be interpreted in context of histology. Prognosis of ETMR remains dismal despite multimodal therapy.

ETMR: a tumor entity in its infancy

Embryonal tumor with Multilayered Rosettes (ETMR) is a relatively rare but typically deadly type of brain tumor that occurs mostly in infants. Since the discovery of the characteristic chromosome 19 miRNA cluster (C19MC) amplification a decade ago, the methods for diagnosing this entity have improved and many new insights in the molecular landscape of ETMRs have been acquired. All ETMRs, despite their highly heterogeneous histology, are characterized by specific high expression of the RNA-binding protein LIN28A, which is, therefore, often used as a diagnostic marker for these tumors. ETMRs have few recurrent genetic aberrations, mainly affecting the miRNA pathway and including amplification of C19MC (embryonal tumor with multilayered rosettes, C19MC-altered) and mutually exclusive biallelic DICER1 mutations of which the first hit is typically inherited through the germline (embryonal tumor with multilayered rosettes, DICER1-altered). Identification of downstream pathways affected by the deregulated miRNA machinery has led to several proposed potential therapeutical vulnerabilities including targeting the WNT, SHH, or mTOR pathways, MYCN or chromosomal instability. However, despite those findings, treatment outcomes have only marginally improved, since the initial description of this tumor entity. Many patients do not survive longer than a year after diagnosis and the 5-year overall survival rate is still lower than 30%. Thus, there is an urgent need to translate the new insights in ETMR biology into more effective treatments. Here, we present an overview of clinical and molecular characteristics of ETMRs and the current progress on potential targeted therapies.

Pontine Embryonal Tumor With Multilayered Rosettes: An Autopsy Case Exhibiting Extensive Posttreatment Glial and Neuronal Maturation

Embryonal tumor with multilayered rosettes (ETMR) is a rare and highly aggressive embryonal central nervous system tumor that primarily affects young children. It is characterized by (1) amplification of the C19MC miRNA cluster at 19q13.42 and (2) immunohistochemical tumor cell positivity for LIN28A. We describe the case of a 3-year-old girl who presented with a 2-week history of multiple neurological deficits. Based primarily on imaging findings that revealed a large pontine tumor, biopsy was not performed and the patient was clinically diagnosed with a "diffuse intrinsic pontine glioma." She was subsequently treated with radiation and concurrent adjuvant temozolomide, but unfortunately there was minimal response and the patient died 6 months after diagnosis. Autopsy revealed an ETMR that was confirmed via C19MC fluorescence in situ hybridization and LIN28 immunohistochemistry. Although widespread central nervous system dissemination was observed, large portions of the main pontine mass exhibited evidence of extensive glial and neuronal maturation (ie, differentiation). We consider this tissue "maturation" to have been induced by chemotherapy and radiation. Herein, we discuss the importance of antemortem biopsy of intrinsic pontine tumors and the clinical significance of glial and neuronal maturation post therapy in the context of ETMR.

Radiation for ETMR: Literature review and case series of patients treated with proton therapy

Background and purpose

Embryonal tumors with multilayered rosettes (ETMRs) are aggressive tumors that typically occur in young children. Radiation is often deferred or delayed for these patients due to late effects; proton therapy may mitigate some of these concerns. This study reviews the role of radiation in ETMR and describes initial results with proton therapy.

Materials and methods

Records of patients with embryonal tumor with abundant neuropil and true rosettes (ETANTR), medulloepithelioma (MEP), and ependymoblastoma (EPL) treated with proton therapy at our institution were retrospectively reviewed. A literature review of cases of CNS ETANTR, MEP, and EPL published since 1990 was also conducted.

Results

Seven patients were treated with proton therapy. Their median age at diagnosis was 33 months (range 10-57 months) and their median age at radiation start was 42 months (range 17-58 months). Their median overall survival (OS) was 16 months (range 8-64 months), with three patients surviving 36 months or longer. Five patients had disease progression prior to starting radiation; all 5 of these patients failed in the tumor bed. A search of the literature identified 204 cases of ETMR with a median OS of 10 months (range 0.03-161 months). Median OS of 18 long-term survivors (≥36 months) in the literature was 77 months (range 37-184 months). Of these 18 long-term survivors, 17 (94%) received radiotherapy as part of their initial treatment; 14 of them were treated with craniospinal irradiation.

Conclusions

Outcomes of patients with ETMR treated with proton therapy are encouraging compared to historical results. Further study of this rare tumor is warranted to better define the role of radiotherapy.

Embryonal tumors with multilayered rosettes in children: the SFCE experience

PURPOSES

The purpose of this study was to retrospectively study embryonal tumors with multilayered rosettes (ETMR), a rare new entity that gathers ETAN-TR (embryonal tumor with abundant neuropil and true rosettes), ependymoblastomas, and medulloepitheliomas, in order to improve their descriptions and try to better define therapeutic modalities.

METHODS

Patients with ETMR, ETAN-TR, ependymoblastoma, and medulloepithelioma treated in SFCE centres (Société Française de lutte contre les Cancers et les leucémies de l'Enfant et de l'adolescent) since 2000 were collected. Data were retrieved from clinical charts.

RESULTS

Thirty-eight patients were included in the analysis. Seventeen had an ETAN-TR, 13 had a medulloepithelioma, and 8 had an ETMR. No ependymoblastoma was included. The median age at diagnosis was 31 months (range, 2.8-141 months). The predominant tumor location was supratentorial (66%); 18.4% patients had metastatic lesion. LIN28A expression was positive in 11/11 patients. Amplification of the locus 19q13.42 was positive in 10/12 patients. Thirty patients were treated according to the primitive neuroectodermal tumors of high risk (PNET-HR) protocol. The median time of follow-up was 0.9 years (range 0.1 to 15.3 years). The 1-year event-free survival (EFS) and overall survival (OS) were, respectively, 36% CI 95% (23-55) and 45% CI 95% (31-64). On multivariate analysis, complete surgical resection, radiotherapy, and high-dose chemotherapy were associated with a better overall survival with a relative risk of, respectively, 7.9 CI 95% (2.6-23.5) p < 0.0002, 41.8 CI 95% (9.4-186) p < 0.0001, and 3.5 CI 95% (1.3-9.5) p = 0.012.

CONCLUSION

Prognosis of ETMR remains dismal despite multimodal therapy. LIN28A immunostaining and 19q13.42 amplification should be systematically done to secure the diagnosis. Complete surgical resection, radiotherapy, and high-dose chemotherapy are associated with better outcome.