Tumor Syndromes: Neurosurgical Evaluation and Management

Primary brain tumours in adults

The most frequent adult-type primary CNS tumours are diffuse gliomas, but a large variety of rarer CNS tumour types exists. The classification of these tumours is increasingly based on molecular diagnostics, which is reflected in the extensive molecular foundation of the recent WHO 2021 classification of CNS tumours. Resection as extensive as is safely possible is the cornerstone of treatment in most gliomas, and is now also recommended early in the treatment of patients with radiological evidence of histologically low-grade tumours. For the adult-type diffuse glioma, standard of care is a combination of radiotherapy and chemotherapy. Although treatment with curative intent is not available, combined modality treatment has resulted in long-term survival (>10-20 years) for some patients with isocitrate dehydrogenase (IDH) mutant tumours. Other rarer tumours require tailored approaches, best delivered in specialised centres. Targeted treatments based on molecular alterations still only play a minor role in the treatment landscape of adult-type diffuse glioma, and today are mainly limited to patients with tumours with BRAFV600E (ie, Val600Glu) mutations. Immunotherapy for CNS tumours is still in its infancy, and so far, trials with checkpoint inhibitors and vaccination studies have not shown improvement in patient outcomes in glioblastoma. Current research is focused on improving our understanding of the immunosuppressive tumour environment, the molecular heterogeneity of tumours, and the role of tumour microtube network connections between cells in the tumour microenvironment. These factors all appear to play a role in treatment resistance, and indicate that novel approaches are needed to further improve outcomes of patients with CNS tumours.

Coexisting lipomatous meningioma and glioblastoma in Cowden syndrome: A unique tumor association

Cowden syndrome (CS) is a rare hereditary hamartoma-cancer disorder related to germline mutations in the tumor suppressor phosphatase and tensin homolog (PTEN) gene. Association of CS with intracranial tumors, apart from Lhermitte-Duclos disease (LDD), is not well recognized. We present an exceptional instance of concomitant meningioma and glioblastoma in CS, the first case ever reported. Following a new-onset seizure, a 62-year-old male harboring the PTEN gene germline mutation c.334C > G was diagnosed with multiple brain tumors, which were erroneously thought to correspond to metastases. Because no primary cancer was found, an operation was proposed for histopathological diagnosis. Examination of surgical specimens obtained from the two lesions removed, one extra-axial and the other intracerebral, demonstrated a metaplastic meningioma with a lipomatous appearance and an isocitrate dehydrogenase wild-type glioblastoma, respectively. Loss of the PTEN gene expression was demonstrated immunohistochemically in both lesions, a finding that supports their relation to CS. A thorough literature review revealed only 25 additional CS patients with intracranial tumors other than LDD. All of them corresponded to primary lesions, with meningiomas accounting for 76% of the cases (19 patients), followed by pituitary tumors (three cases) and glioblastomas (two patients from the same family). Our report and literature review highlight the association between CS and primary brain tumors rather than metastasis. For judicious management of a CS patient with multiple intracranial tumors, different primary brain pathological entities should also be suspected first before considering metastasis. Close neurological monitoring and brain magnetic resonance imaging are advocated as part of the cancer screening in CS patients, particularly in cases with a family history of intracranial tumors.