Clinicopathologic features of small cell glioblastomas

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.

Dramatic clinical response in the treatment of small cell glioblastoma multiforme

What is known and objective

Small cell glioblastoma (scGBM) is a rare subtype of primary glioblastoma, which typically behave more aggressively compared with classical glioblastoma (GBMs). They are generally associated with poor responses to treatment, and optimal treatment is not known.

Case summary

We present the case of a 51‐year‐old woman with scGBM with O⁶‐methylguanine DNA methyltransferase (MGMT) promoter methylation, demonstrating an unexpected dramatic clinical response to chemoradiotherapy.

What is new and conclusion

This case highlights that treatment with temozolomide‐based chemoradiotherapy is justified in patients with scGBM, despite their poor prognosis. MGMT methylation may be associated with clinical responses.

Cerebral hemispheric glioblastoma with PNET-like morphology and histone H3.3 G34 mutation in younger patients: Report of three rare cases and diagnostic pitfalls

Recurrent mutations in H3F3A that encodes the histone 3 variant H3.3, lead to amino acid substitutions including K27M and G34R/V-which are observed in high-grade gliomas (HGGs) of children and young adults. Previous studies have focused on gliomas with K27M mutation, whereas gliomas with G34R/V mutation have received little attention. Herein, we report three rare cases of glioblastoma (GBM) with H3.3 G34 mutation arising from a cerebral hemisphere in two children and one young adult. All three cases showed microscopic characteristics of central nervous system primitive neuroectodermal tumor (CNS-PNET, called CNS embryonal tumors in WHO 2016 Revised 4^th Edition) and presented H3.3 G34 mutation. H3.3 G34-mutant brain tumors were formerly a group of histopathologically distinct neoplasms, involved in GBM, CNS-PNET, and astroblastoma. However, recent studies have demonstrated that different CNS tumors with H3.3 G34 mutation display coherent epigenetic signatures, implying a single biological origin. Correspondingly, our three cases showed high consistency in tumor location, histological morphology, and molecular phenotype. Their immunophenotypes are similar to astrocytoma, with ATRX loss and TP53 mutation. Therefore it suggests that these H3.3 G34-mutant brain tumors may be a rare entity of HGG.

Small cell glioblastoma multiforme: a case series and clinicopathological update

Small cell glioblastoma (scGBM) is a rare histological variant of classical glioblastoma (GBM). Presence of necrosis and microvascular proliferation is not essential for the diagnosis. It is thought to have more aggressive behavior as compared with classical GBM; however, because of its rarity standard treatment guidelines are not available. Adjuvant treatment for these cancers consists of postoperative radiotherapy with concurrent and maintenance temozolomide similar to classical GBM. Here we present a case series of five small cell glioblastoma patients along with the clinical-pathological review.

An anaplastic pleomorphic xanthoastrocytoma with periventricular extension: An autopsy case report and review of the literature

Pleomorphic xanthoastrocytomas (PXAs) are rare low-grade astrocytic tumors that typically present as superficial nodular cystic tumors of the cerebrum attached to the leptomeninx. Histologically, they are pleomorphic, hypercellular glial neoplasms. Despite the presence of microscopic pleomorphism, patients' postoperative prognosis is generally good. Anaplastic PXAs (APXAs) have a high mitotic index and patients with APXAs have a worse prognosis than patients with PXAs. Here, we report an autopsy case of APXA initially diagnosed as PXA. After gross total resection, the tumor recurred and was diagnosed as an APXA; thereafter, the patient died. An autopsy revealed that the tumor had relapsed at the primary site and had spread to the leptomeningeal space while concurrently invading the cerebrum including the periventricular area forming multifocal lesions. The histological findings of the autopsy were similar to those for epithelioid glioblastoma (EGBM) and small cell glioblastoma (SCGBM). In particular, the periventricular area with multifocal lesions was composed of SCGBM-like cells. It has been shown that multifocal lesions are frequently identified in patients with SCGBM. This is the first histopathologically confirmed case of APXA-related tumor presenting with periventricular extension and multifocal lesion formation. The periventricular extension might be a feature of PXAs and APXAs. However, suspected periventricular spread on imaging in past cases of PXAs and APXAs might instead represent the malignant transformation of these tumors to glioblastoma-like high-grade tumors, which often show SCGBM-like histological patterns.

Small Cell Glioblastoma of the Sella Turcica Region: Case Report and Review of the Literature

BACKGROUND

Glioblastomas in the sellar region are very rare; in most cases, the tumor originates from the optic nerve or optic chiasm. Only 4 cases of sellar glioblastoma with a nonoptic origin have been reported. We present such a case with detailed clinical, imaging, and histopathologic information. We also review similar published cases.

CASE DESCRIPTION

A 42-year-old woman presented with endocrinologic abnormalities, including amenorrhea and lactation, symptoms of diabetes insipidus, and signs of elevated intracranial pressure. Magnetic resonance imaging showed a giant, heterogeneously enhancing lesion involving the intrasellar, parasellar, and suprasellar regions, with hypercellularity and signs of infiltration of adjacent structures. Intraoperative examination revealed the tumor to be independent from the optic pathways, but it showed infiltration of the hypothalamic region. Histopathologic examination demonstrated uniformly packed small cells and negative staining for glial fibrillary acidic protein, which was consistent with a diagnosis of small cell glioblastoma.

CONCLUSIONS

This is the first report of a small cell glioblastoma in the sella turcica region. Glioblastomas in the sellar region with no clear evidence of an optic origin should be viewed as an independent disease entity. The typical characteristics of this tumor indicate it should be considered a rare subtype of glioblastoma. Further accumulation of experience is needed to better differentiate these cases and to offer optimal treatment.