Journal de pathologie clinique et expérimentale

Abstrait

Malignant Glioma with Primitive Neuroectodermal Components: Clinical and Pathologic Features with Treatment Modalities of Five Cases

Tara Kimbason, Scott G Turner, Syed Aj Kazmi, Edward Fourgas, Thomas Gergel, Lynn Belles, Angela Whitmire, Michel Lacroix and Steven A Toms

The classification of primary brain tumors poses many challenges. Glioblastoma multiforme (GBM) is the most common primary adult primary brain tumor, representing more than 50% of all cases. They are composed of cells of astrocytic origin and are characterized by infiltration into the brain parenchyma, making surgical cure impossible. Although local radiation and chemotherapy are routinely employed to treat these aggressive tumors, they invariably progress with survival on the order of two years or less. In contrast, primitive neuroectodermal tumors (PNET) typically occur in children and are composed of poorly differentiated neuroepithelial cells histologically similar to medulloblastoma which may disseminate through the cerebral spinal fluid (CSF). The response of PNETs to chemotherapy is variable but tends to be better than for GBM but usually poorer than for medulloblastoma.

Rarely, tumors with features of both malignant glioma and PNET occur, possibly arising from expansion of stem cell populations located within GBM. These mixed tumors pose not only a diagnostic challenge, but also a therapeutic challenge: while GBM is typically treated with alkylating agents, such as temozolomide or nitrosoureas, PNETs typically respond to platinum-based chemotherapy.

We report a series of five patients with this rare mixed tumor. All patients underwent resection followed by radiation and chemotherapy. Their clinical courses and treatments varied and one of the patients was treated with Optune Tumor Treating Fields (TTF). Their specific histologic features, radiographic presentation, and response to chemotherapy and TTF are discussed. We believe early, aggressive therapy with a combination of treatment modalities, including platinum-based chemotherapy may be beneficial for these rare, mixed tumors.