Rhabdoid glioblastoma: a recently recognized subtype of glioblastoma

Radiation-induced intracranial rhabdomyosarcoma- A rare complication: Report of a case with literature review

Radiation-induced sarcoma (RIS) of the central nervous system is an uncommon late complication of radiation therapy. We report a case of a 47-year-old male patient who underwent surgery followed by irradiation and chemotherapy with temozolomide for a frontal lobe gliosarcoma and presented 43 months later with a recurrent tumor in the same location with interval growth in the size of the lesion. Histology from surgical resection of the recurrent tumor revealed embryonal rhabdomyosarcoma (RMS). Adjacent brain parenchyma showed radiation-induced changes. There was no evidence of gliosarcoma at recurrence. In addition to the rarity of sarcomas arising following irradiation for glial tumors, this case represents one of the first reports of an intracerebral RMS arising in this setting.

Systematic Review and Individual Patient Data Analysis of Uncommon Variants of Glioblastoma: An Analysis of 196 Cases

OBJECTIVES

Different variant of GBM has been reported viz. Epithelioid Glioblastoma (GBM-E), Rhabdoid GBM (GBM-R), Small cell GBM (GBM-SC), Giant cell GBM (GBM-GC), GBM with neuro ectodermal differentiation (GBM-PNET) with unknown behavior.

MATERIALS

We conducted a systematic review and individual patient data analysis of these rare GBM variants. We searched PubMed, google search, and Cochrane library for eligible studies till July 1^st 2016 published in English language and collected data regarding age, sex, subtype and treatment received, Progression Free Survival (PFS), Overall Survival (OS). Statistical Package for social sciences (SPSS) v16 software was used for all statistical analysis.

RESULTS

We retrieved data of 196 patients with rare GBM subtypes. Among these GBM-GC is commonest (51%), followed by GBM-R (19%), GBM-PNET (13%), GBM-SC (9%) and GBM-E (8%). Median age at diagnosis was 38, 40, 43.5, 69.5 and 18 years, respectively. Male: female ratio was 2:1 for GBM-E, and 1:3 for GBM-SC. Maximal safe resection followed by adjuvant local radiation was used for most of the patients. However, 6 patients with GBM-PNET, 3 each of GBM-E, GBM-SC received adjuvant craniospinal radiation. Out of 88 patients who received chemotherapy, 64 received Temozolomide alone or combination chemotherapy containing Temozolomide. Median PFS and OS for the entire cohort were 9 and 16 months. In univariate analysis, patient with a Gross Total Resection had significantly better PFS and OS compared to those with a Sub Total Resection [23 vs. 13 months (p-0.01)]. Median OS for GBM PNET, GBM-GC, GBM-SC, GBM-R and GBM-E were 32, 18.3, 11, 12 and 7.7 months, respectively (P = 0.001). Interestingly, 31.3%, 37.8% of patients with GBM-E, GBM-R had CSF dissemination.

CONCLUSION

Overall cohort of rarer GBM variant has equivalent survival compared to GBM not otherwise specified. However, epithelioid and Rhabdoid GBM has worst survival and one third shows CSF dissemination.

Confirming Diagnosis and Effective Treatment for Rare Epithelioid Glioblastoma Variant: An Integrated Survival Analysis of the Literature

BACKGROUND

Epithelioid glioblastoma (eGBM) is a very rare histologic variant of glioblastoma that has not been studied in isolation and, therefore, its optimal management has been largely assumed, but not confirmed. The aim of this study was to analyze all reported cases describing the presentation and clinical features to better understand the clinical significance of this histologic diagnosis.

METHODS

A comprehensive literature search was conducted from 2005 to April 2019 identifying cases of eGBM that satisfied selection criteria for analysis. Survival was investigated using Kaplan-Meier estimations, and then univariate and multivariate logistic regression analyses for primary end point overall survival (OS) and second end point progression-free survival (PFS).

RESULTS

A total cohort of 59 eGBM cases from 28 articles were included for final analysis. Median age of patients at diagnosis was 30 years, with 29 (46%) female patients. When reported, 100% (37/37) cases were IDH1-wild-type and 63% (19/30) were positive for the BRAF V600E mutation by immunohistochemistry. Median OS and PFS were estimated to be 11.0 months (95% confidence interval, 6.5-13.0) and 7.0 months (95% confidence interval, 3.0-10.0), respectively. Surgical extent of resection, radiation therapy, and chemotherapy all predicted superior OS and PFS on multivariate analysis (P < 0.05). No biomarkers prognosticated survival.

CONCLUSIONS

These findings indicate that the histologic diagnosis of eGBM does not deviate from the clinical course of the broader glioblastoma diagnosis, despite being a unique histologic identity. These results argue against the temptation to deviate from the traditional management paradigm of surgery, radiation, and chemotherapy for glioblastoma based on this histology alone.

Magnetic Resonance Imaging Features of Rhabdoid Glioblastomas

PURPOSE

Rhabdoid glioblastoma (rGB) is a recently described, highly aggressive brain tumor, in which glioblastoma (GB) is associated with a rhabdoid component. So far only 21 cases have been reported and its imaging findings have not been studied in detail. In this paper, we present 11 additional cases and aim to depict detailed magnetic resonance imaging (MRI) features of this tumor in comparison with the previous cases of rGBs and our cohort of typical GBs.

METHODS

Retrospective evaluation of the glass slides of 249 GB patients disclosed 14 cases with rhabdoid morphology. Eleven of these cases with available MRI were included in the study. Immunohistochemistry was also performed. MRI and clinicopathologic findings were compared with those of previous rGBs and typical GBs.

RESULTS

(1) rGB is usually a large, well-delineated solid tumor with extensive necrosis, heterogeneous contrast enhancement, occasional hemorrhage, and cysts, (2) rGB may present at an older age than previously reported, but still in younger individuals compared with typical GB patients, (3) tumor dissemination in the form of leptomeningeal seeding and more rarely extracranial metastases is a feature of rGBs, although leptomeningeal seeding may not be as high as previously reported, (4) prognosis is poor in rGBs.

CONCLUSIONS

rGB is a new entity which has not yet appeared in the WHO classification of central nervous system (CNS) tumors. Understanding its clinical and imaging features may help to distinguish it from other tumors of CNS.