Brain Tumors

Glioblastoma (IDH-wildtype) is the most common and most aggressive primary malignant brain tumor in adults. It is classified as grade 4 in the World Health Organization (WHO) classification and tends to grow rapidly and infiltrate surrounding brain tissue.

Meningioma is a usually benign tumor arising from the arachnoid cells of the membranes (meninges) covering the brain and spinal cord. It is the most common extra-axial intracranial mass in adults and accounts for roughly one third of primary brain tumors. The World Health Organization (WHO) grades it as grade 1, 2 or 3.

Astrocytoma is the most common group of glial tumors, arising from the brain's supporting cells, the astrocytes. The 2021 World Health Organization (WHO) classification redefined astrocytomas by IDH mutation status, treating IDH-mutant astrocytoma as a distinct disease from IDH-wildtype glioblastoma.

Oligodendroglioma is a slow-growing diffuse glioma arising from the brain's myelin-producing oligodendrocytes. According to the 2021 World Health Organization (WHO) classification, the diagnosis requires the combined presence of an IDH mutation and 1p/19q co-deletion. It has the most favorable prognosis among diffuse gliomas.

Ependymoma is a central nervous system tumor arising from the ependymal cells lining the brain's ventricles and the central canal of the spinal cord. The 2021 World Health Organization (WHO) classification divides ependymomas into subgroups based on anatomical location and molecular features. Complete surgical resection is the most important prognostic factor in treatment.

Medulloblastoma is the most common malignant brain tumor in children. It arises in the cerebellum, is classified as grade 4 in the World Health Organization (WHO) classification, and can spread via the cerebrospinal fluid. It requires multidisciplinary treatment combining surgery, radiotherapy and chemotherapy.

Brain metastases are secondary tumors that form when a cancer from another part of the body spreads to the brain. They are the most common group of intracranial tumors in adults and are far more frequent than primary brain tumors. Treatment requires a multidisciplinary approach tailored to the type of primary cancer and the features of the metastases.

Primary central nervous system lymphoma (PCNSL) is an aggressive type of lymphoma that begins in the brain, eyes, leptomeninges or spinal cord and does not spread to other parts of the body. The large majority of cases are diffuse large B-cell lymphoma in histology. Treatment is based not on surgical resection but on high-dose methotrexate-based chemotherapy.

Diffuse midline glioma (DMG, H3 K27-altered) is a highly aggressive brain tumor arising in midline structures (brainstem, thalamus, spinal cord) in children. Formerly known as diffuse intrinsic pontine glioma (DIPG), it is classified as grade 4 in the World Health Organization (WHO) classification.

ATRT (atypical teratoid rhabdoid tumor) is an extremely rare and aggressive embryonal brain tumor of infants and young children. It is characterized by loss of the SMARCB1 (rarely SMARCA4) gene and is classified as grade 4 in the World Health Organization (WHO) classification.

Esthesioneuroblastoma (olfactory neuroblastoma) is a rare malignant neuroectodermal tumor arising from the olfactory epithelium in the upper nasal cavity. It grows slowly but behaves in a locally invasive manner, and can extend through the skull base into the anterior cranial fossa.

Pineal region tumors are a heterogeneous group of various tumor types arising from the pineal gland and surrounding structures, located deep in the brain between the third and fourth ventricles. Treatment and outcome depend largely on the tumor type.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that can arise from the meninges (dura). It closely resembles meningioma on imaging; distinction is made by pathological and molecular analysis. The NAB2::STAT6 gene fusion is the molecular hallmark of the disease.

Choroid plexus tumors are rare tumors arising from the choroid plexus epithelium that produces cerebrospinal fluid (CSF) within the brain ventricles. They span a spectrum from benign papilloma (grade 1) to malignant carcinoma (grade 3) and occur particularly in infants.

Hemangioblastoma is a benign (WHO grade 1) vascular tumor of the central nervous system. It occurs most often in the cerebellum and is one of the more common adult posterior fossa tumors. About a quarter of cases are associated with the inherited Von Hippel-Lindau (VHL) disease. Complete surgical removal is curative in most cases.

Prolactinoma is a benign tumor arising from the anterior pituitary that secretes excess prolactin (a pituitary neuroendocrine tumor, PitNET). It is the most common functional pituitary tumor and is markedly more frequent in women than men. Unlike other pituitary tumors, its first-line treatment is medical therapy with dopamine agonists rather than surgery.

A growth hormone (GH)-secreting pituitary tumor leads to excess GH and IGF-1 in the blood. In adults it produces acromegaly, marked by gradual enlargement of the hands, feet and face; in children, before the growth plates close, it causes gigantism. Although it is a benign pituitary neuroendocrine tumor (PitNET), untreated disease produces important systemic complications.

An ACTH-secreting pituitary tumor stimulates the adrenal glands to overproduce cortisol, causing Cushing's disease. Cushing's disease is the most common cause of endogenous Cushing's syndrome. Although it is a benign pituitary neuroendocrine tumor (PitNET), uncontrolled cortisol excess produces serious systemic consequences.

Craniopharyngioma is a tumor of the pituitary region (sellar/suprasellar) arising from epithelial remnants of the embryonic Rathke's pouch. Although histologically benign (WHO grade 1), it is clinically difficult to manage because of its proximity to vital structures such as the hypothalamus, optic chiasm and pituitary stalk. It shows two age peaks, in childhood and adulthood.

Vestibular schwannoma (acoustic neuroma) is a benign (WHO grade 1) tumor arising from the Schwann cells of the balance (vestibular) division of the 8th cranial nerve. It accounts for the great majority of cerebellopontine angle (CPA) tumors. Its most common symptom is unilateral, slowly progressive hearing loss. Most cases are sporadic; a small proportion are associated with inherited Neurofibromatosis type 2 (NF2).

Non-functioning pituitary adenomas are tumors arising from the pituitary gland that do not cause a clinical syndrome of hormone excess. Because they grow slowly, they are usually diagnosed at a large size (macroadenoma) with symptoms from pressure on surrounding structures.

Chordoma and chondrosarcoma are rare, locally aggressive malignant tumors arising from the skull base bones. Chordoma develops from embryonic notochord remnants and chondrosarcoma from cartilage tissue; they are considered together because of their similar location and treatment.

Glomus tumors (paragangliomas) are mostly benign but locally invasive, highly vascular tumors arising from the glomus bodies of the head and neck. Types located in the temporal bone and skull base can present with pulsatile tinnitus and cranial nerve symptoms.