Anaplastic pilocytic astrocytoma

Pilocytic astrocytoma with anaplastic features presenting good long-term clinical course after surgery alone: a case report

“…In many reported cases, adjuvant therapies were often applied as postoperative treatments for anaplastic PAs [3,9,13,16]. Unlike our case, typical clinical features of anaplastic PAs are adult age (a median age of 26-35 years) and malignant transformation, according to previous reports [1,18,19]. Although it might be interesting to investigate the relationship between these factors (patient's age and onset type) and the prognosis, further collection of case series is needed, because anaplastic PAs are very rare and poorly understood.…”

“…In most papers, histological features of anaplastic PAs were characterized by increased cellularity, multiple mitoses, pseudopalisading necrosis, and endothelial cell proliferation in addition to typical findings such as eosinophilic granular bodies and Rosenthal fibers [1,9,10,13,18,19]. Genetic alterations, such as BRAF, RAF1, and NF1 gene, which may be involved in the development of PAs have also been recently investigated by genomic studies [14].…”

“…PAs with anaplastic features or anaplastic PAs were seen in 2 to 5 % of PA cases [18]. The clinical outcomes of anaplastic PAs were reported to be corresponding to WHO grade II or III gliomas [12,13,16,18], and therefore, some articles suggested that anaplastic PAs needed the postoperative radiation and chemotherapy due to aggressiveness such as early local recurrence and dissemination [1,16,19]. Most of anaplastic PAs have been reported to occur as a secondary transformation from ordinary PAs with exposure to ionizing radiation [3,9,13,16,19].…”

Heterogeneity of histopathological presentation of pilocytic astrocytoma – diagnostic pitfalls. A review

“…It has been documented that anaplastic/malignant transformation of PA occurred most often in association with previous ionizing radiation [75] or surgery alone [88], whereas spontaneous malignant transformation was unique [10,72,90]. The majority of anaplastic cases have been described in adults [10,101]. Nevertheless, PAs with anaplastic features do not always exhibit a clear correlation between morphology and tumour behaviour.…”

“…The pilomyxoid variant of pilocytic astrocytoma (PMA) is suggested to represent a subtype with more invasive growth and increased risk of recurrences [49,50]. Occasionally, the classic PA may exhibit the distinct histological features of anaplasia such as necrosis, mitoses and vascular proliferation [10,25,31,53,82,90,101]. Some other factors, including partial resection, brainstem location and adult age, are also associated with a worse prognosis [27].…”