Calcified Pilocytic Astrocytomas and Calcifying Pseudoneoplasms of the Neuraxis: A Diagnostic Challenge

Pilocytic astrocytoma (PA), recognized as the most prevalent central nervous system (CNS) tumor, has long been associated with calcifications, a characteristic often attributed to benign or indolent growth patterns. In this study, we explored the calcified attributes in these tumors that beckon a deeper understanding. This is a retrospective study, on a set of seven cases, with a histopathological diagnosis of pilocytic astrocytoma with calcifications and psammoma bodies (PB). Despite an encouraging overall survival outcome, the recurrence in four cases cast some doubt on the conventional classification. The histological study of these cases revealed a spectrum of calcifications, varying in size and morphology, all of which exhibited positive reactivity to glial fibrillary acidic protein (GFAP), osteoconduction, and osteopontin. Notably, the immunohistochemistry showed hyaline bodies displaying an atypical immune profile, strikingly negative for vimentin and GFAP, and a robust positivity for epidermal growth factor receptors (EGFR), tumor necrosis factor-alpha (TNF-α), and interleukin 1 beta (IL-1β). These results stimulated speculation that the identity of these calcified tumors may have extended and potentially embraced the realm of calcifying pseudoneoplasms of the neuraxis (CAPNON), underscored by intense pilot gliosis. This study transcends mere anatomical exploration; it delves into the intricacies of calcified tumors, casting a spotlight on the dynamic interplay between PA and CAPNON. As we traverse the frontiers of neuro-oncology, these findings pave the way for innovative avenues in the diagnostics and therapeutics of these tumors.

Spinal Ependymomas: An Updated WHO Classification and a Narrative Review

Ependymomas are neuroepithelial tumors that develop from ependymal cells found in the brain parenchyma and can spread to any part of the spinal cord. Three to six percent of all malignancies affecting the central nervous system (CNS) are ependymomas. Even the most talented surgeons are challenged by spinal cord ependymomas; as a result, research into this clinical phenomenon should continue. Since 1979, the World Health Organization (WHO) has published a classification and grading system for CNS malignancies to ensure consistent diagnostic standards worldwide. The WHO prepared an update on these tumors, paying particular attention to molecular techniques to categorize the therapeutic management of each patient with greater accuracy and clarity. We thoroughly reviewed the literature on the epidemiology, etiology, diagnosis, and treatment of spinal ependymomas since there has not been a recent review of these tumors. This included modifications to the 2021 WHO Classification of Tumors of the Central Nervous System.

Teratoma With Malignant Ectomesenchymoma in the Pineal Region: A Case Report

Tumors involving the pineal gland include germinomas, non-germinomatous, and parenchymal tumors. Sometimes these tumors can be differentiated into rhabdomyosarcoma, which is an aggressive and rapidly recurring sarcoma but is a rare event. We present the case of a 23-year-old male, with an eight-year-long history of a non-treated brain tumor compatible with a teratoma. Chemotherapy and radiotherapy were offered, and two years later, malignant transformation to astrocytoma, rhabdomyosarcoma, neural cell carcinoma, ganglioglioma, and low-grade chondrosarcoma was noted. Immunohistochemistry was valuable in differentiating these entities that confirmed the diagnosis. Malignant transformations may be secondary to the normal transformation of multipotent embryonic cells into more developed tissues after radiotherapy of teratoma and malignant ectomesenchymoma transformation.