A 15 year old boy with a posterior fossa tumor

A Recurrent Pleomorphic Xanthoastrocytoma in the Cerebellum in a Young Adult: A Case Report and Review of the Literature

Pleomorphic xanthoastrocytoma (PXA) is a rare glioma. It accounts for less than 1% of all astrocytomas. About 98% of PXAs originate supratentorially with the temporal lobe being the most common location. Cases of infratentorial PXAs are rarely reported in the medical literature. The tumor presents with a wide variation of symptoms based on the neuroanatomy involved with the location and size of the tumor, with seizures being the most reported symptom. The diagnosis depends on histological and clinical features along with radiologic features. We searched the keywords "Pleomorphic xanthastrocytoma, PXA, cerebellum, infratentorium, astrocytoma, gliomas" in the PubMed database; from 1979 to the current date, 28 cases were found in the medical literature featuring PXA in the infratentorium. We present the 29th case in the literature and the first in Syria. Our patient had a lesion in the right cerebellum and presented with a history of intermittent headache for 5 months followed by progressive gait disturbances and blurry vision and was misdiagnosed at the time of presentation with a high-grade glioma which is a common confusion because of the histological and clinical similarities. The patient underwent a suboccipital craniotomy, and adjuvant therapy with a combination of radiotherapy and chemotherapy with temozolomide was initiated at first. Then, the patient presented with a relapse of symptoms and went through another surgery where frozen sections suggested the diagnosis of PXA; further histopathological and immunohistochemical studies confirmed the diagnosis. Alongside highlighting the diagnostic challenge of this rare tumor, we did a brief review of the literature.

Cerebellar Pleomorphic Xanthoastrocytoma with BRAF V600E Mutation

BACKGROUND

Pleomorphic xanthoastrocytoma (PXA) is a rare type of astrocytoma with a peak incidence from 10 to 19 years of age. PXA is found most commonly in the supratentorium. When it is present in atypical areas such as the infratentorium, it is often overlooked as a potential differential diagnosis.

CASE DESCRIPTION

This report discusses the case of an 18-year-old woman with a pure PXA in the left cerebellum. The case consists of interesting pathologic and molecular features which do not align with the literature about PXA: a positive finding for BRAF V600E mutation and a negative finding for cluster of differentiation 34 expression. A review of pure PXA cases in the infratentorium has also been completed.

CONCLUSIONS

To our knowledge, this is the first case of PXA in the infratentorium with BRAF V600E mutation. The case also highlights the clinical relevance of including PXA as a differential diagnosis for lesions of the infratentorium.

Pleomorphic xanthoastrocytoma in the posterior fossa: a case report with advanced neuroimaging findings

Pleomorphic xanthoastrocytoma (PXA) is a rare glioma usually occurring in children and young adults. It is a benign World Health Organization (WHO) grade II tumor that accounts for <1% of all astrocytomas. Its occurrence in the infratentorial compartment is rare, and the cerebellum is the most common of the unusual locations. Few case reports have described conventional imaging features of these tumors, but none has reported the advanced magnetic resonance (MR) neuroimaging features in dynamic susceptibility perfusion-weighted imaging (DSC-PWI), diffusion weighted-imaging (DWI) and MR spectroscopy. Therefore, the purpose of this study is to report a case of PXA in the cerebellum of a 28-year-old patient and discuss the MR advanced imaging characteristics compared to the more common PXA supratentorial type.

Demography, Pattern of Care, and Survival in Patients with Xanthoastrocytoma: A Systematic Review and Individual Patient Data Analysis of 325 Cases

Objectives Xanthoastrocytoma (XA) is a low-grade glial tumor seen in young adults and there is lack of robust data on treatment of this rare tumor. In this systematic review and individual patient's data analysis, we aimed to look into the demography, pattern of care, survival outcomes, and prognostic factors in patients with both Grade II and III XA.

Methods A comprehensive search was conducted with the Medical Subject Heading terms: “Xanthoastrocytoma; Pleomorphic Xanthoastrocytoma; Anaplastic Xanthoastrocytoma; Xanthoastrocytoma AND treatment; and Anaplastic Xanthoastrocytoma AND survival” to find all possible publications.

Results A total of 325 individual patients from a total of 138 publications pertaining to XA were retrieved. Median age of the entire cohort was 19 years. About 56.1% of the patients underwent a gross total resection (GTR) and 31.4% underwent a subtotal resection. Nearly, 76.6% of the patients had a Grade II tumor and adjuvant radiation was delivered in 27.4% of the patients. Estimated 2- and 5-year progression-free survival (PFS) were 68.5 and 51.2%, respectively. Age, grade, and extent of surgery were significant factors affecting PFS. Estimated 2- and 5-year overall survival (OS) was 88.8 and 78%, respectively. The median OS for Grade II and Grade III tumors were 209 and 49 months, respectively. Age and extent of surgery were significant factors affecting OS.

Conclusion XA is a disease of young adults with favorable prognosis. Younger patients (<20 years), patients who undergo a GTR, and patients with a lower grade tumor have a better treatment outcome.

An Infratentorial Pure Pleomorphic Xanthoastrocytoma Arising from Middle Cerebellar Peduncle: A Rare Location of an Uncommon Tumor

BACKGROUND

Pleomorphic xanthoastrocytomas are rare tumors of glial origin comprising <1% of all astrocytic tumors of brain. These tumors are rare in the infratentorial compartment and were not known to arise from the middle cerebellar peduncle.

CASE DESCRIPTION

We discuss the case of a 16-year-boy who presented with altered sensorium and features of increased intracranial pressure and was found to have a 4 × 4 × 3 cm mass arising from the middle cerebellar peduncle.

CONCLUSION

We also discuss the histopathologic features of these tumors suggesting their resemblance to other maldevelopmental tumors, the rarity of pure World Health Organization grade II pleomorphic xanthoastrocytoma in the infratentorial compartment, as well as the appropriate management.

Melanosomal melanin pigment in pleomorphic xanthoastrocytoma, evidence for neuronal-glial origin: A case report with review of the literature

We describe a unique case of pleomorphic xanthoastrocytoma (PXA) in a 19-year-old male presenting with the chief complaint of seizures. On radiology, the tumor was located in the temporal lobe. It was cortically based and solid cystic in nature. Light microscopy showed pleomorphic large polygonal cells with inclusions, nuclear clustering, lipidization, and foamy cytoplasm intermingled with spindle cells arranged in sweeping pattern and focally containing cytoplasmic brownish black pigment. The pigment stained black with Fontana-Masson stain and bleached with potassium permanganate. Gomori silver stain showed reticulin fibers surrounding individual tumor cells as well as groups of cells. On immunohistochemistry, tumor cells were positive for GFAP, S-100 and focally for synaptophysin and CD34 but negative for HMB-45. CD34 revealed a specific membranous pattern around individual cells as well as groups of cells along the fibers replicating a reticulin pattern. The ultrastructural examination showed supporting melanosomes, thus confirming the melanin pigment. Sequencing for BRAF V600E showed a heterozygous mutation. To our knowledge only five cases of PXA with melanin pigment have been reported and none of which described BRAF V600E mutation analysis. This case provides further insight into the origin and pathogenesis of pigmented astrocytic tumor, additionally highlighting the characteristic CD34 staining pattern.

Pleomorphic Xanthoastrocytoma: Natural History and Long-Term Follow-Up

Prognostic significance of histological anaplasia and BRAF V600E mutation were retrospectively evaluated in 74 patients with pleomorphic xanthoastrocytoma (PXA). Median age at diagnosis was 21.5 years (31 pediatric, 43 adult) and median follow-up 7.6 years. Anaplasia (PXA-AF), defined as mitotic index ≥ 5/10 HPF and/or presence of necrosis, was present in 33 cases. BRAF V600E mutation was detected in 39 (of 60) cases by immunohistochemical and/or molecular analysis, all negative for IDH1 (R132H). Mitotic index ≥ 5/10 HPF and necrosis were associated with decreased overall survival (OS; P = 0.0005 and P = 0.0002, respectively). In all cases except two, necrosis was associated with mitotic index ≥ 5/10 HPF. Patients with BRAF V600E mutant tumors had significantly longer OS compared with those without BRAF V600E mutation (P = 0.02). PXA-AF patients, regardless of age, had significantly shorter OS compared with those without (P = 0.0003). Recurrence-free survival was significantly shorter for adult PXA-AF patients (P = 0.047) only. Patients who either recurred or died ≤ 3 years from diagnosis were more likely to have had either PXA-AF at first diagnosis (P = 0.008) or undergone a non-gross total resection procedure (P = 0.004) as compared with patients who did not. This study provides further evidence that PXA-AF behaves more aggressively than PXA and may qualify for WHO grade III "anaplastic" designation.

23-year-old man with a superficial cortical brain tumor

A 23-year-old male presented with a tonic-clonic generalized seizure. Neuroradiological examination revealed a superficial cystic mass with a mural nodule in the right fronto-parietal lobe. Histological and immunohistochemical examination were consistent with a pigmented (melanin producing) desmoplastic ganglioglioma.These tumors have been first described in childhood, one of them displaying melanin deposits. Only twenty cases of non-infantile desmoplastic gangliogliomas have been reported in the literature, none of them pigmented. According to the clinical and histomorphology (including the desmoplastic component) features, the differential diagnosis should include the ganglioglioma, the xanthoastrocytoma pleomorphic (both tumors also with pigmented forms) and the superficial desmoplastic infantile astrocytoma.

Malignant potential of pleomorphic xanthoastrocytoma

Pleomorphic xanthoastrocytoma (PXA) is a low-grade astrocytic tumour that occasionally progresses to a higher grade. We have extensively reviewed the literature on the potential for malignant transformation of PXA. An illustrative case of a PXA transforming to glioblastoma multiforme is presented.

Pigmented pleomorphic xanthoastrocytoma: a rare variant and literature review

A 16-year-old male teenager presented with seizure and loss of consciousness for 20 min. Magnetic resonance imaging demonstrated a mass occupying the right medial temporal lobe. Histological examination revealed a non-pigmented area with spindle-shaped and large xanthomatous pleomorphic cells and a pigmented region with pigmented neoplastic cells with fascicular arrangement. Immunohistochemical studies showed the tumor was positive for GFAP and low index of Ki-67. Considering the patient's history, clinical data and pathological findings, we rendered a rare variant named pigmented pleomorphic xanthoastrocytoma.