Unpredictable Evolution of Pilocytic Astrocytoma in Adults: A Case Series and Diagnostic Challenges.

BACKGROUND Pilocytic astrocytomas are WHO grade 1 tumors frequently identified in children and young adults, with a male predominance. This pathology is uncommon in adults, representing 0.8% of central nervous system tumors. The significance of these tumors is underscored by their recurrence rates, which are 38.9% following subtotal resection and 4% after complete resection. This study presents 4 cases of female patients, aged between 58 and 76 years, managed in our service in the last 15 years. CASE REPORT Clinical manifestations (headache, nausea, and vomiting) were nonspecific. Imaging helped in 1 case. In 3 cases, imaging caused confusion by indicating either a stroke (1 case) or metastases (2 cases). Diagnosis was determined through histopathological examination. Immunohistochemical assays were conducted to confirm the diagnosis (IDH1, Ki-67, Nestin, and p53) and to evaluate the prognosis and risk of progression/recurrence of the cases (MGMT and PTEN). Of the 4 cases, there was 1 case of tumor progression and 1 of death. Two cases presented a favorable evolution, surviving without disabilities 5 years after diagnosis. We compared our results with other studies and observed similarities and differences between patients, including variations in age and sex. CONCLUSIONS This rare tumor's nonspecific symptomatology and imaging make diagnosis and prognosis difficult. The cases illustrate the significant role of immunohistochemical assays in diagnosing and evaluating patient prognosis. The clinical applicability of these tests must be corroborated with clinical presentation and neurosurgical resection to highlight progression and recurrence rates. Standardized protocols and molecular-based evidence are essential for optimizing patient management and outcomes.