Abstract 547P
Background
To analyze clinicopathological features of ETMRs.
Methods
A total of 14 cases of ETMRs from 2016 to 2021 in Xuanwu Hospital of Capital Medical University were retrospectively summarized. The clinical and imaging characteristics, pathological and molecular characteristics were analyzed, and the related literature was reviewed.
Results
All 14 patients (6 males and 8 females) aged from 9 months old to 3 years old (mean 2 years) mainly had a history of headache or/and vomiting. Twelve tumors were supratentorial and two infratentorial, seven of which occurred in the frontal lobe. The MRI findings showed that the lesions were located in the third ventricle, and the enhanced MRI showed abnormal enhancement signals. The MRI enhancement all showed an abnormal enhancement signal. Pathological finding showed that 12 cases had displaying the morphological characteristics of ETMR. The distribution of tumor cells is sparse and uneven, and some cells arrange in multiple layers and grow around blood vessels, partially forming a "Homm-rett group" structure, island-like structure can be seen. IHC showed Syn and Lin28a were immunopositive in all 14 cases (14/14). GFAP and Olig-2 were partially immunopositive in 3 cases (3/14). EMA was dot-and/or-ring immunopositivity in 2 cases (90%, 2/14). At the same time, there was a case immunopositive for H3K27M, with the loss of H3K27me3. 12 ETMRs were available to detect C19MC and Dicer1 gene mutation. 11 in 12 (88.9%) were found to have C19MC amplification, and one have Dicer1 mutation as well as H3K27M mutation. Among the 14 patients after surgery, All 10 patients received adjuvant radiotherapy/chemotherapy,Progression-free survival was 6.2 months, and overall survival was 11 months.
Conclusions
ETMRs have relatively distinguishing clinical and histopathological features. C19MC alteration and Dicer1 gene mutation, can be considered as useful biomarkers for the diagnosis and differential diagnosis, and provide a direction for targeted therapy in the future.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
612P - Updated results from the multicenter phase II study of fruquintinib plus mFOLFOX6/FOLFIRI as first-line therapy in advanced metastatic colorectal cancer (mCRC)
Presenter: fuxiang zhou
Session: Poster session 10
613P - Effect of prior use of anti-VEGF agents on overall survival in patients with refractory metastatic colorectal cancer: A post-hoc analysis of the phase III SUNLIGHT trial
Presenter: Gerald Prager
Session: Poster session 10
614P - Effect of KRASG12 mutations on overall survival in patients with refractory metastatic colorectal cancer: A post-hoc analysis of the phase III SUNLIGHT trial
Presenter: Josep Tabernero
Session: Poster session 10
615P - The impacts of starting regorafenib dose on treatment outcomes in metastatic colorectal cancer
Presenter: Satoshi Yuki
Session: Poster session 10
616P - Sequential treatment with regorafenib (REG) and trifluridine/tipiracil (TAS) +/- bevacizumab (Bev) in refractory metastatic colorectal cancer (mCRC) in community clinical practice in the USA
Presenter: Tanios Bekaii-Saab
Session: Poster session 10
618P - Efficacy and safety of vactosertib and pembrolizumab combination in patients with previously treated microsatellite stable metastatic colorectal cancer
Presenter: Tae Won Kim
Session: Poster session 10
619P - Pelareorep + atezolizumab and chemotherapy in third-line (3L) metastatic colorectal cancer (mCRC) patients: Interim results from the GOBLET study
Presenter: Guy Ungerechts
Session: Poster session 10
620P - A phase II trial evaluating the activity of cabozantinib in pre-treated patients with metastatic colorectal cancer (mCRC): ABACO trial initial molecular data
Presenter: Giulia Martini
Session: Poster session 10
621P - The systemic proteome of consensus molecular subtypes from patients with RAS wild-type metastatic colorectal cancer: Analysis from the randomized phase II PanaMa (AIO KRK0212) trial
Presenter: Alexej Ballhausen
Session: Poster session 10