Efficacy of various extent of resection on survival rates of patients with pilocytic astrocytoma: based on a large population

Pilocytic astrocytoma (PA) is classified as a Grade I benign neuroglial tumor. The extent of surgical resection is a critical factor influencing the prognosis for patients with PA. In prior researches of PA, the extent of surgical resection is generally categorized into GTR, STR and biopsy. In some researches on brain tumor surgeries, the extent of resection also includes GTL. There is no existing research specifically comparing the efficacy of GTR versus GTL in PA treatment. In this study, the data we used are from the SEER database. We categorized the extent of resection into GTL, GTR, STL, STR, biopsy, and no surgery based on SEER classification of surgical procedures, to investigate the impact of extent of resection on PA patient survival. A multivariate logistic regression model was utilized to acquire odds ratios (OR) for different extent of resection. Survival outcomes across different extent of resection (GTL, GTR, STL, STR, biopsy, no surgery) were assessed using Kaplan-Meier survival curve analysis, with curve comparisons conducted via log-rank tests. The impact of various risk factors on survival was assessed using the Cox proportional hazards model. The hazard ratio (HR) was employed to quantify the influence of one or more factors on overall survival throughout the follow-up period. Multivariate Cox analysis revealed that age, tumor location, extent of resection, as well as the application of radiotherapy and chemotherapy, all significantly impacted prognosis. Compared to GTL, GTR did not significantly increase the risk of mortality (HR 1.17; 95% CI 0.73-1.86, p = 0.5). Furthermore, there was no statistically significant difference between the Kaplan-Meier survival curves of the two groups (p = 0.18). We employed propensity score matching (PSM) to balance the differences in baseline characteristics of patients receiving chemotherapy or radiotherapy. A total of 4429 patients were included in this study. Age, diagnosis period, race, tumor size, and tumor location as influential on the extent of resection. Age, tumor location, extent of resection, and application of radiotherapy and chemotherapy influenced the survival of PA patients. The Kaplan-Meier survival curves revealed that the long-term survival rate for GTR is slightly higher than that for GTL. The PSM analysis revealed that the application of radiotherapy and chemotherapy was associated with the reduction of overall survival in PA patients. In conclusion, there was no significant difference in survival between GTR and GTL, so GTR with less damage was preferred. The application of radiotherapy and chemotherapy can reduce overall survival of patients with PA.

Astrocytoma with high-grade features and MYBL1-MMP16 fusion

Background

Gliomas represent the most common primary intraparenchymal brain tumors in adult and pediatric patients. Neuropathological work-up of these gliomas typically entails the determination of isocitrate dehydrogenase (IDH) mutational status, presence or absence of 1p/19q co-deletion, and O6 methylguanine-DNA methyl-transferase (MGMT) promoter methylation status.

Case Description

We present here an unusual case of a posterior fossa tumor in a 51-year-old female, which was initially diagnosed as astrocytoma with some high-grade features that recurred, displaying even more aggressive features such as infiltration and increased proliferative activity. Both the initially resected and recurrent tumor revealed MYBL1-MMP16 fusion, which is much more commonly found in pediatric low-grade gliomas and, to our knowledge has not been described in the context of an adult glioma.

Conclusion

The significance of MYBL1-MMP16 fusion in adult gliomas in relation to survival and likelihood of recurrence is, therefore, unknown and requires more extensive research.

Clinical, histopathological and molecular risk factors for recurrence of pilocytic astrocytomas: brainstem/spinal location, nestin expression and gain of 7q and 19 are associated with early tumor recurrence

Pilocytic astrocytomas (PAs) are benign tumors. However, clinically aggressive PAs despite benign histology have been reported, and histological and molecular risk factors for prognosis have not been elucidated. 38 PAs were studied for clinical, histological, and molecular factors, including tumor location, extent of resection, post-operative treatment, glioma-associated molecules (IDH1/2, ATRX, BRAF, FGFR1, PIK3CA, H3F3A, p53, VEGF, Nestin, PD-1/PD-L1), CDKN2A/B deletion, and chromosomal number aberrations, to see if there is any correlation with patient's progression-free survival (PFS). Brainstem/spinal location, extent of resection and post-operative treatment, and VEGF-A, Nestin and PD-L1 expression, copy number gain of chromosome 7q or 19, TP53 mutation were significantly associated with shorter PFS. None of the histological parameters was associated with PFS. Multivariate analyses demonstrated that high Nestin expression, gain of 7q or 19, and extent of removal were independently predictive for early tumor recurrence. The brainstem/spinal PAs appeared distinct from those in the other sites in terms of molecular characteristics. Clinically aggressive PAs despite benign histology exhibited high Nestin expression. Brainstem/spinal location, extent of resection and some molecular factors including Nestin expression and gains of 7q and 19, rather than histological parameters, may be associated with early tumor recurrence in PAs.

Primary intramedullary spinal cord pilocytic astrocytoma with anaplasia in an adult: illustrative case

BACKGROUND

Primary intramedullary spinal cord (IMSC) pilocytic astrocytoma (PA) with anaplasia is extremely rare.

OBSERVATIONS

A 50-year-old man presented to our hospital with numbness of the left posterior rib region, back, and bilateral lower limbs. Contrast-enhanced T1-weighted magnetic resonance imaging (MRI) revealed an intramedullary lesion at T2–T3 with no contrast enhancement. The patient opted for conservative treatment. Eighteen months after the first consultation, the patient presented with slowly progressive numbness of the bilateral upper limbs, paraparesis, and dysuria, with rapid deterioration over the following 3 months. T1- and T2-weighted MRI revealed expansion of the intramedullary lesion, which extended from C7 to T5, and syringomyelia at C5–C6. Contrast-enhanced T1-weighted MRI revealed an enhancing intramedullary lesion at C7–T5. Open biopsy and C5–T5 laminectomy were performed for diagnosis and decompression. PA with anaplasia was diagnosed based on pathological and immunohistochemical findings. The patient received postoperative radiotherapy and chemotherapy.

LESSONS

Rapidly progressive IMSC PA with a change in contrast enhancement is extremely rare in adults. PA may undergo a spontaneous malignant transformation during its natural clinical course. In this case, the change in contrast enhancement may have been associated with the malignant transformation of the PA.

Rapid Recurrence and Anaplastic Transformation of a Pilocytic Astrocytoma in an Elderly Patient: Case Report and Review of the Literature

BACKGROUND

Rapid recurrence of a pilocytic astrocytoma with anaplastic transformation is extremely rare. The case of an elderly patient with a cerebellar pilocytic astrocytoma with anaplastic transformation during short-term follow-up is reported.

CASE DESCRIPTION

An 83-year-old woman presented initially with dizziness and a gait deviation to the right. Magnetic resonance imaging demonstrated a homogeneously enhanced mass in the right cerebellar hemisphere, and the tumor was subtotally removed by right suboccipital craniotomy. Histologic examination showed that the tumor cells contained eosinophilic cytoplasm and spindle-shaped processes with Rosenthal fibers and eosinophilic granular bodies, diagnosed as a typical pilocytic astrocytoma (PA). The MIB-1 index was <1%. The patient did not receive postoperative adjuvant radiation and chemotherapy. Two months after surgery, magnetic resonance imaging showed growth of the residual tumor adjacent to the fourth ventricle, causing obstructive hydrocephalus. She underwent surgery again, and the tumor was totally removed. Histologic findings showed mitotic cells and increased cellularity compared with the primary tumor, which was compatible with anaplastic transformation of PA with a MIB-1 index of 50%. Postoperatively, she was observed with best supportive care without postoperative adjuvant therapy. Nine months after the second operation, she died due to tonsillar herniation and obstructive hydrocephalus caused by a recurrent tumor. An autopsy was performed.

CONCLUSIONS

It is extremely rare, as in the present case, that a cerebellar PA in an elderly patient recurs rapidly with anaplastic transformation, despite deferred postoperative adjuvant therapy including radiation and chemotherapy. A novel molecular-targeted therapy is needed for anaplastic PA showing aggressive biological behavior.

Malignant Transformation of a Rosette-Forming Glioneuronal Tumor to Glioblastoma

BACKGROUND

A rosette-forming glioneuronal tumor (RGNT), a rare brain tumor, presents as a benign feature with a favorable outcome. To date, a few cases with aggressive behaviors, such as recurrence or dissemination, but none with malignant transformation, have been reported. We describe 1 case that recurred as glioblastoma after complete resection of the benign RGNT.

CASE DESCRIPTION

A man aged 58 years presented with headache and dizziness without neurologic symptoms. Magnetic resonance imaging showed a 4 × 2.5 cm, well-demarcated mass in the left cerebellar hemisphere. The patient underwent gross total resection of the tumor and a diagnosis of RGNT was made. There was no evidence of recurrence on serial follow-up. However, a recurrent heterogeneous enhancing mass in the previous surgical cavity was observed on a 7-year postoperative magnetic resonance imaging scan. Reoperation was performed and a histopathological study revealed a glioblastoma.

CONCLUSIONS

To the best of our knowledge, this is the first case of spontaneous malignant transformation of an RGNT. Our case may be helpful in better understanding the biological behavior and clinical outcome of RGNT. We emphasize the malignant potential of this rare tumor and the necessity of future large-scaled research for most appropriate therapeutic strategies.

Recent Progress in the Pathology and Genetics of Pilocytic and Pilomyxoid Astrocytomas

Pilocytic and pilomyxoid astrocytomas are some of the most common gliomas in children and young adults. These gliomas are indolent neoplasms with long overall survival probability. The genetic characteristics of these neoplasms are well known, and our deepened understanding of their associated molecular alterations has led to the development of novel treatment strategies and approaches. Currently, we can account for some of the unusual behavior, such as oncogene-induced senescence, associated spontaneous regression, anaplastic transformation, and cerebrospinal dissemination, of these gliomas. Nevertheless, enigmatic issues continue to surround these chronic tumors. Here, we review the classical and uncommon clinical pathological and genetic features of these indolent gliomas.

Promoter methylation of RB1, P15, P16, and MGMT and their impact on the clinical course of pilocytic astrocytomas

Promoter methylation of P15, P16, RB transcriptional corepressor 1 (RB1) and O-6-methylguanine-DNA methyltransferase (MGMT) impacts the prognosis of numerous glioma subtypes. However, whether promoter methylation of these genes also has an impact on the clinical course of pilocytic astrocytoma remains unclear. Using methylation-specific polymerase chain reaction, the methylation status of the tumor suppressor genes P15, P16, RB1, and MGMT in pilocytic astrocytomas (n=18) was analyzed. Immunohistochemical staining for the R132H mutation of the isocitrate dehydrogenase (NADP(+)) 1, cytosolic (IDH1) gene was performed. Clinical data including age, gender, localization of tumor, extent of resection, treatment modality, progression-free survival and overall survival were collected. The methylation index for P15, P16, RB1 and MGMT was 0.0, 0.0, 5.6% (1/18) and 44.5% (8/18), respectively. If the MGMT promoter was methylated, the probability of relapse and second subsequent therapy was significantly increased (P=0.019). The one patient with methylation of P15 demonstrated a poor clinical course. The pilocytic astrocytomas of all 18 patients revealed wild-type IDH1. Clinically, there was a significant correlation of subtotal resection with the occurrence of relapse (P=0.005) and of the localization of the tumor with the extent of resection (P=0.031). Gross total resection was achieved significantly more often in pediatric patients than in adult patients (P=0.003). Adult patients demonstrated more relapses following the first tumor resection (P=0.001). The present study indicates that methylation of MGMT is associated with a poor clinical course and represents an age-independent risk factor for an unfavorable outcome. Other influential factors of outcome were the age of the patient and extent of resection.

Supratentorial Pilocytic Astrocytoma Mimicking Convexity Meningioma with Early Anaplastic Transformation: A Case Report

Meningiomas and pilocytic astrocytomas are benign intracranial tumors. Pilocytic astrocytomas arises frequently at the posterior fossa in childhood. Meningiomas have several image findings, such as a dural tail sign, bony erosion, and sunburst appearance on angiography. However, pilocytic astrocytomas with these findings have been rarely reported. In this report, we describe a mass with typical image findings of a meningioma, but diagnosed as a supratentorial pilocytic astrocytoma with early anaplastic transformation.

Adult anaplastic pilocytic astrocytoma - a diagnostic challenge? A case series and literature review

INTRODUCTION

Anaplastic pilocytic astrocytoma (APA) is an exceptionally rare type of high-grade glioma in adults. Establishing histopathological diagnosis is challenging and its clinical and radiological appearance insidious. By this case series and first literature review we investigated the various clinical, neuroradiological, and histopathological features of APA in adults.

METHODS

An in hospital screening of the database from the Institute of Pathology was conducted to identify cases of APA. Further, we performed a literature review in PubMed using the keywords "anaplastic/malignant/atypical AND pilocytic astrocytoma" and "anaplastic astrocytoma/glioblastoma AND Rosenthal fibers" and summarized the current knowledge about APA in adults.

RESULTS

Over the last decade we were able to identify 3 adult patients with APA in our hospital. According to the pertinent literature, the prognosis of APA in adults (documented survival of up to 10 years) appears to be better than in other high-grade gliomas. Few cases were associated with neurofibromatosis type 1, which seems to predispose for development of APA. Although molecular genetics is still of limited value for differentiation of APA from other high-grade glioma, advanced neuroimaging techniques such as magnetic resonance perfusion imaging and spectroscopy allow improved differential work-up. In particular, APA in adults has the ability to mimic various neurological diseases such as tumefactive demyelinating lesions, low-, or high-grade gliomas.

CONCLUSIONS

Although currently not explicitly recognized as a distinct clinico-pathologic entity it seems that adult APA behaves differently from conventional high-grade glioma and should be included in differential diagnostics to enable adequate patient care. However, further studies are needed to better understand this extremely rare disease.

The use of fluorescein sodium in the biopsy and gross-total resection of a tectal plate glioma

Intravenous administration of fluorescein sodium fluoresces glioma burden tissue and can be visualized using the surgical microscope with a specialized filter. Intraoperative guidance afforded through the use of fluorescein may enhance the fidelity of tissue sampling, and increase the ability to accomplish complete resection of tectal lesions. In this report the authors present the case of a 19-year-old man with a tectal anaplastic pilocytic astrocytoma in which the use of fluorescein sodium and a Zeiss Pentero surgical microscope equipped with a yellow 560 filter enabled safe complete resection. In conjunction with neurosurgical navigation, added intraoperative guidance provided by fluorescein may be beneficial in the resection of brainstem gliomas.