Brain Tumors : Clinical Features, Classification & Risk Stratification

Metastasis is the most common brain tumor overall, and the cerebrum is the most common site of metastasis. Lung cancer is the most common site of initial tumors, and breast cancer is the most common source of leptomeningeal spread. 

Meningioma is the most common primary brain tumor, while astrocytoma is the most frequent brain tumor in children. Medulloblastoma is the most prevalent malignant brain tumor in children. Medulloblastoma is the most prevalent tumor that is radiosensitive.  Pituitary adenoma is the most common suprasellar lesion in adults; craniopharyngioma is the most common tumor with calcification in children. These are the three most common suprasellar lesions.

Clinical Features Of Brain Tumours

Herniation syndromes, which cause the displacement of the brain stem, compression of the parenchyma and other critical structures including nerves and veins, are the causes of the clinical symptoms of brain tumors. 

Cortical involvement is the cause of seizures. Elevated intracranial pressure: Morning headache that is quite bad; Papilla edema, Throwing up. Non-specific elevated intracranial pressure (m/c nerve), sixth cranial nerve palsy. The X-ray shows the skull to be silver-beaten.
Supratentorial tumors can present with psychiatric symptoms.

Involvement of Frontal Lobe   

A frontal lobe involvement results in personality alterations.
• Unsociable conduct.
• The syndrome of witzelsucht, or abnormal laughter.
• Indecent behavior in public.
• Broca's aphasia, which occurs when the dominant side's inferior frontal lobe is affected.

Involvement of Temporal Lobe

The following conditions are caused by involvement of the temporal lobe: psychosis; Wernicke's aphasia (Area 22) in the superior temporal gyrus; superior quadrantanopia (due to involvement of Meyer's loop). Visual agnosia, characterized by a patient's failure to recognize objects that are typical in daily life; also known as Kluver-Bucy syndrome.

Involvement of Parietal Lobe

Features consist of: Contralateral weakness, inferior quadrantanopia (caused by superior fiber involvement), Paraesthesia, Incapacity.

Gerstman syndrome: This condition, which has four symptoms and is caused by dominant parietal lobe involvement, is hemi-neglect.
Acrylia, incalculia, and perplexity to the right of left .  Inability to recognize fingers.

Involvement of Occipital Lobe       

Cortical blindness (sometimes called Anton syndrome) is caused by occipital lobe involvement; the patient denies blindness despite being blind. Visual flaws vary depending on the region in question.
The Balint syndrome. There are three parts to it.  Concurrent diagnosis.  Optical ataxia; oculomotor apraxia.

Investigations

For practically all cancers, contrast-enhanced MRI is performed. The contrast agent employed is gadolinium. It is the preferred method of investigation for all tumors.

Management

Surgery is typically the only course of action when a patient exhibits clinical signs of elevated intracranial pressure as a result of a malignant tumor. Further treatment is administered in accordance with the tumor kind as reported in the histology report.

There are two short-term strategies that can assist in lowering intracranial pressure (ICP). Among the interim actions are:

Anti-epileptic drugs: used to treat people with seizures and to prevent seizures in the first place. The use of steroids can lessen tumoral edema. One of the most often utilized steroids is dexamethasone.

Osmotic agents: 3% hypertonic saline, mannitol, and Lasix (furosemide) are two examples. 

CSF Diversion: Tumors frequently restrict the flow of CSF, which results in hydrocephalus and elevated intracranial pressure. CSF diversion offers some momentary comfort in these situations.

Depending on the tumor's histology report, surgery—either a craniotomy or craniectomy—followed by chemotherapy and radiation therapy is the most effective treatment for the majority of malignancies.

Goals of The Surgery

To lower the elevated ICP. To remove tumors as safely as possible; To acquire tissue sample for immunohistochemistry and histology.

Classification Of Brain Tumors

Bailey and Cushing classified brain tumors for the first time in 1926.
The WHO classification from 2016 is currently used to categorize brain cancers. Primary Brain Tumors: Meningeal meningioma; Glial astrocytoma, ependymoma, glioblastoma multiforme, choroid plexus tumor Neurofibroma, a tumor of the nerve sheath.

Tumors of the embryo: medulloblastoma, PNET (primitive neuroendocrine tumors), etc. Vascular tumors, such as angioma and angiosarcoma. Other cancers include those of the pituitary, pineal gland, and germ cells. Metastasis and occurrence of secondary brain tumors: they might be either sporadic (most prevalent) or syndromic or familial.

Risk Factors

The risk factors include: Exposure to radiation chemicals, such as pesticides; Genetic flaws, such as vascular-endothelial growth factor receptor deficiencies and epidermal growth factor receptor defects.
Viruses such as JC virus, adenovirus 12, and simian virus 40.

Gliomas

Their source is glial cells.

The aforementioned comprise: Astrocytomas, which originate from astrocytes; Oligodendrogliomas, which originate from oligodendrocytes; Ependymomas, which originate from ependymal cells; and Choroid Plexus Tumors, which originate from choroid plexus.

Astrocytomas

Astrocytes are the source of them. There are two primary types: the diffuse variety, which includes glioblastoma multiforme, and the circumscribed variety, which includes pilocytic astrocytoma, plomatomyxoid astrocytoma, subependymal giant cell astrocytoma, etc.
Diffuse varieties are distinct entities unto themselves.

Differences Between Adult And Pediatric Astrocytomas

Adult astrocytomas are primarily supratentorial; the cerebral cortex is the most common site; and most adult tumors are high grade. Most pediatric astrocytomas are infratentorial; the cerebellum is the most common site; most pediatric tumors are low grade.

Who Grading Of Astrocytoma

• Grade 1- Pilocytic astrocytoma. They have the best prognosis and complete resection is curative.
• Grade 2- Diffuse astrocytoma
• Grade 3- Anaplastic astrocytoma
• Grade 4- Glioblastoma multiforme which has the worst prognosis.
  • Hallmark of glioblastoma multiforme is intratumoral necrosis.
  • Common immunohistochemistry markers for glial tumors are GFAP (Glial fibrillary acidic protein) And S 100

Pilocytic Astrocytoma

The histopathological characteristics of pilocytic astrocytoma are hyaline droplets, rosenthal fibers, and eosinophilic granular aggregates.
The source of pilocytic astrocytomas is "Radial Glia."

Glioblastoma Multiforme

The cerebral cortex is the most prevalent place; It has the poorest prognosis. Glioblastoma multiforme is treated with the "STUPP" Regimen, which combines concurrent chemotherapy and radiation therapy. Cisplatin and carmustine are among the chemotherapy medications utilized. 

Response assessment criteria, such as Mac Donald's criteria and Response Assessment in Neuro Oncology (RANO), are available for patients who have already received treatment. 

Radiation therapy is completely contraindicated in children under three years old. In youngsters younger than seven years old, it should be avoided as much as possible. Chemotherapy is used to extend the period of crisis for children under three years old who have had glioma surgery.  Intratumor necrosis is the pathological hallmark of glioblastoma multiforme.

Oligodendrogliomas

The source of their genesis is the oligodendrocyte, which is in charge of central myelination. They make up 10% of gliomas in total.
Anaplastic is classified as grade 3, while oligodendrogliomas are classified as grade 2. The frontal lobe is where oligodendrogliomas are most frequently found. 1p/19 q A particular genetic entity called co-deletion is linked to a favorable prognosis and a remarkable response to chemotherapy, particularly temozolomide. 

Calcifications are present in 80 percent of oligodendrogliomas in clinical practice. Pathological characteristics unique to oligodendrogliomas include: The typical feature of oligodendrogliomas is chicken wire calcifications, or calcifications along the blood arteries.
Fried egg/honeycomb cytoplasm, which is a result of cytoplasmic enlargement.

The preferred method of investigation is Contrast Enhanced MRI. The surgical approach is Maximal Safe Resection followed by Chemotherapy and Radiotherapy. 

The following chemotherapy medications are used to treat oligodendrogliomas: proparbazine, bevacizumab, vincristine, and locustine. Methionine The test used to distinguish between low-grade astrocytoma and oligodendroglioma is called PET. Methionine uptake is quite high in oligodendrogliomas while it is relatively low in low grade astrocytomas. 

In 80% of cases, oligodendrogliomas exhibit calcification. In gradient echo (GRE) images obtained from MRIs, calcifications are specifically visible. MRIs can produce a variety of pictures. T2; T1; Susceptibility Diffusion weighted imaging, GRE imaging, and weighted imaging 

Ependymoma                                 

It originates from ependymal cells, which border the spinal cord's ventricles and central canal. Additionally, these are the most typical spinal cord malignancies. The fourth ventricle is the most frequent location in the brain. The fourth ventricle is also the most common site in youngsters.  The most common site in the spinal cord is filum terminale. The most common histopathological form is myxopapillary ependymoma. 

Because the tumor is located in the ventricular cavity, there is a greater likelihood of cerebrospinal fluid dispersal, which worsens the prognosis.
Ependymal pseudorosette and true rosettes are among the histopathological characteristics of ependymomas. Dissemination of cerebrospinal fluid is a characteristic of ependymomas frequently.
As a result, radiation to the craniospinal axis is frequently performed after surgery.

Hemangioblastoma

It is also referred to as a Lindau tumor or cyst.  Angioreticuloma -  Among adults, it is the most typical primary intra-axial posterior fossa tumor.  Cerebellum is the most frequently found region in the posterior fossa. A cerebellar sign may also be present, although elevated ICP is the most typical manifestation. The preferred method of investigation is Contrast Enhanced MRI. Cyst with mural nodule is the most frequent radiological appearance. 

A mural nodule-containing cyst is also observed in astrocytomas. The characteristic that sets astrocytomas apart Cyst wall enhancement is present in MRIs but missing in hemangioblastomas. Hemangioblastoma is inherited; 80% of cases are sporadic About 20% of cases are familial or syndromic. Von Hippel-Lindau syndrome (VHL) is the most prevalent syndrome linked to hemangioblastoma. Nine to forty percent of individuals with hemangioblastoma have erythrocytosis, which is caused by an increase in erythropoietin production.

The most significant and highly vascular component of the tumor in hemangioblastoma is a mural nodule. The entire tumor is removed as part of the treatment. Renal cell carcinoma is the most frequent cause of death for patients with Von Hippel Lindau. External beam radiation is used to treat VHL patients with numerous lesions.

Meningioma

The most prevalent primary tumor not originating from the brain is meningioma. It is the most prevalent tumor both extraaxially and intracranially. They start as arachnoid cap cells or meningothelial cells of arachnoid. Owing to estrogen receptors, meningiomas are more frequent in women. 

Benign meningiomas grow slowly and cause mass consequences.
Calcification, which is visible in 25–30% of cases, is one of the radiological characteristics of meningiomas on CT scans (contrast or non-contrast).  Bony hyperostosis is another defining trait. Stunning contrast enhancement is visible on an MRI. One of the classic signs of meningioma is the dura mater indication. Take note: pseudo-dural sign is observed in metastases and astrocytomas. Noted are indications that are wide based.  There is a CSF sleeve encircling the tumor.         

Treatment

 The meningioma is treated with complete excision. The Simpson's grading system is used to determine the amount of tumor removal.
For WHO grade I meningiomas, the Simpson grading scale is regarded as the gold standard for determining the surgical degree of resection.
Grade one is optimal when the tumor is completely removed together with the dura mater and bone. The worst is grade four. In certain instances, a dura mater edge of 2 cm is deemed to be in grade 0. Histopathological characteristics such as psammoma bodies are observed in meningiomas.

Because the brainstem and other important organs and pathways are involved, piano playing fingers are observed in foramen magnum meningioma. Radiosurgery or Gamma Knife surgery is used for tumors smaller than 3 cm that are in places that are difficult to reach physically.

Pituitary Adenoma

The anterior pituitary is often the site of pituitary adenoma.  Prolactinomas are the most prevalent kind of pituitary adenoma.
Pituitary adenoma comes in three different forms: A micropituitary adenoma, a tumor less than 10 mm in size. A macropituitary adenoma characterized by a tumor larger than 10 mm. Massive pituitary adenoma, defined as a tumor larger than 4 cm. Reticulin stain is a useful tool for distinguishing pituitary adenoma from hyperplasia.
Usually, these tumors develop in the third or fourth decade of life.

Clinical Features

The following causes the classical general clinical features: • Hyperptuituitarism in non-functioning tumors. Hyper-secretion syndromes observed in tumors in operation. The cause of visual involvement is compression of the optic nerve. 

When a tumor extends into the cavernous sinus, it can cause many cranial nerve palsies as well as involve the internal capsule.
Among the distinct clinical characteristics are: Galactorrhea, amenorrhea, and infertility are brought on by prostatons.
Growth hormone-secreting tumors can cause acromegaly in adults and gigantism in youngsters. Tumors secreting thyrotropic hormone from the adrenal cortex are the source of Cushing's syndrome.

Non-functioning tumors, such as null cell adenoma, do not secrete hormones and manifest late in life. Functioning tumors, such as prolactinoma, secrete hormones and manifest early in life. 

Investigations

The "Pituitary protocol" for contrast-enhanced MRI is followed, resulting in 2 mm sellar incisions. A paranasal sinus CT scan is performed for an operating perspective. An extensive hormonal profile and an ophthalmological examination are performed.

Treatment

The only pituitary adenomas that are managed medically are prostactinomas. The use of dopamine agonists such as cabergoline and bromocriptine. The tumor shrinks with these medications in 6 to 8 weeks.  Rhinorrhea or a cerebrospinal fluid leak is the side effect.

Indications of Surgery

In cases where medical therapy is not working to shrink the tumors; Tumor enlargement that persists;  Pituitary apoplexy; Drug intolerance. 

Growth Hormone Secreting Tumors

Clinical Features Include

Diabetes mellitus; spade-like hand; beetle brow; concentric cardiac hypertrophy.

Treatment

The preferred course of treatment for: Tumors that continue to develop
Pituitary apoplexy; significant loss of eyesight. To achieve initial stabilization, medical management is provided, which consists of:
Octreotide reduces the volume of tumors by 30% and growth hormone release by 70%. Sandostatin and Pasireotide LAR. Additionally, dopamine agonists and the growth hormone receptor antagonist pegvisomant are employed.

Surgical Details

The most used technique is trans-sphenoidal, and the most popular path is trans-nasal-trans-sphenoidal resection. The tools that can be utilized are endoscopy and a microscope. A craniotomy may be required for suprasellar extension tumors.

Complications of Surgery

Rhinorrhea from a cerebrospinal fluid leak, meningitis, and hyperpigmentation (perhaps treated with hormone replacement).

Note

In cases with several hormonal shortages, thyroid hormone, steroids, and rest may be administered in that order. When there is a tumor recurrence or subtotal or incomplete excision, postoperative radiation therapy is administered. In surgery, the mucosal flap known as a hadad-bassagasteguy is employed to cover the dura defect. 

The Sphenopalatine artery's septal branch serves as the foundation for this mucosal flap. When lesions are recurrent or residual, radiosurgery or gamamma knife surgery are utilized. Pituitary tumors can be classified using the Hardy and modified Hardy Wilson classifications; the radiological classification is known as the "knosp" classification.

Medulloblastoma

The most prevalent location of this tumor is the midline cerebellar vermis in children and the cerebellar hemispheres in adults. Medulloblastoma is the most common primary malignant brain tumor in children. It is also the most radiosensitive tumor. The Obersteiner granule cell layer in the superior medullary velum is the source of medulloblastoma. Tumor's relationship to the fourth ventricle
Generally speaking, medulloblastoma is the tumor type that grows from the roof; ependymoma is the tumor type that arises from the floor.

Clinical Features

The primary cause of them is increased intracranial pressure, Vertigo and dysphagia, Cerebellar symptoms, Brain stem symptoms also exist, depending on the degree of brainstem involvement. Raised intracranial pressure symptoms are more noticeable in youngsters than in adults, when cerebellar indications are more noticeable. 

CSF dissemination is another tendency of medulloblastoma. For this reason, post-surgery craniospinal axis irradiation is administered in cases of medulloblastoma. Homer Wright rosettes can be seen on histology; Chang Staging (TNM) is the staging method used.
Examination of options MRI with contrast enhanced

Treatment: 

Complete tumor resection followed by craniospinal axis irradiation is the definitive treatment for medulloblastoma; however, as most patients have hydrocephalus, CSF diversion may be necessary. Since radiation therapy cannot be administered to children under the age of three, chemotherapy is used instead. 

Risk Stratification in Medulloblastoma

Standard/Average risk: Patients with no metastases, a residual tumor less than 1.5 cm2, and an age greater than 3 years are at average risk.
High risk: The prognosis is bad for patients who have metastasized, have a residual tumor larger than 1.5 cm2, or are younger than 3 years old.

Craniopharyngioma

Originating from Rathke's Pouch of the embryonic pharynx, this benign tumor is the most frequent juvenile tumor of non-glial origin.
The distribution of ages is bimodal. The age range for the first peak is 5 to 10 years old, and the second peak occurs between 55 and 60 years old.  Two forms of craniopharyngiomas exist histopathologically.  The most prevalent kind, Adamantinomatous, in youngsters  The most prevalent form in adults, the papillary type.  The majority of the tumor is situated in the traditional suprasellar area.

Clinical Features

Adults typically have endocrine characteristics such as hypopituitarism.
Signs of elevated intracranial pressure are the most typical presentation feature in youngsters. Additional attributes - Stunted growth; Endocrine problems; and visual abnormalities. Diabetes insipidus is a trait in youngsters.

Diagnosis

 The tumor appears primarily solid and cystic upon physical inspection; the cyst contains machine oil fluid. It gets its name from the fact that the fluid contains cholesterol crystals and looks like machine oil. The preferred investigation is MRI with contrast enhancement. More than 90% of computer tomography patients show evidence of calcification. This type of cerebral tumor is the most prevalent and has the highest calcification incidence.

Treatment Consists of 2 Parts: 

Hormonal workup comes initially. The following order should be followed for replacing the inadequacies following the completion of the hormonal workup. Thyroid hormones should be restored first, then steroids, and finally other hormones. These patients need to have their hormones replaced permanently. 

Excision is the second phase of treatment. Two surgical techniques: craniotomy and endoscopic cyst decompression Radiotherapy after cerebral spinal fluid diversion and biopsy. Bleomycin instillation intracytoplasmically. To avoid recurrence, post-operative radiation therapy is unquestionably necessary.  Hormone replacement therapy is required for life.

Primary CNS Lymphoma

The most prevalent kind of lymphoma is Non-Hodgkin's lymphoma, with Diffuse Large B Cell lymphoma being the most common subtype.  While big cell variants and anaplastic variations are common in immunocompromised individuals, diffuse large B cell lymphoma is more common in immunocompetent individuals. The incidence of primary CNS lymphoma has increased during the past few years, mostly as a result of immunosuppression in transplant patients and an increase in HIV/AIDS infections.

Because the primary CNS lymphoma occasionally totally disappears after steroid treatment, it is also characterized as a "Ghost Cell Tumor."
Therefore, when a CNS lymphoma is suspected, a stereotactic guided biopsy is required to provide a clear diagnosis. Medication should not be started until the biopsy confirms the diagnosis. Should medicine be initiated prior to the tumor biopsy, Before the biopsy, if medicine is started, the tumor may go away, making the diagnosis impossible.

Clinical Features

are symptoms such as seizures and localized neurological impairments that indicate elevated intracranial tension. The preferred method of investigation is stereotactic guided biopsy. Only after the biopsy should steroid treatment begin. Chemotherapy and external beam radiation therapy are the treatments administered to non-AIDS patients. 

Whole brain radiation therapy (WBRT), methotrexate, and highly active anti-retroviral therapy (HAART) are utilized in AIDS patients. The prognosis is usually not good. If coexisting diseases such as AIDS and transplant ? additional worse prognosis.

Metastatic Tumors

The majority of brain tumors are these. Lung carcinoma is the most common original tumor, while breast carcinoma is the most common primary for leptomeningeal spread.

Differences Between Age Groups And Site Of Primary

 Leukemia is more prevalent than lymphoma as primary cancers in children under the age of 10 to 15 years old. In contrast, osteosarcoma is more common than rhabdomyosarcoma among individuals in the same age range who have solid tumor metastases. Germ cell tumors are the most common type of tumor in people between the ages of 15 and 21. The most prevalent types of malignancies in the age range of the fifth to seventh decade are skin tumors, lung cancer, and breast cancer.

Location

The frontal lobe is the most often occurring region in the cerebrum, which is supra-tentorial. The cerebellum ranks second in frequency, followed by the brainstem. Patients tend to have numerous metastases in about 70% of cases.

Treatment

 Metastasectomy is the only available therapeutic option, and it is limited to three lesions. If there are more than three lesions, surgery is not recommended. Whole brain radiation therapy should be considered if there are four or more lesions. Among the medications frequently used in chemotherapy are paclitaxel, gemcitabine, neveline, and cisplatin. 

Although these medications are found to be less helpful in patients who have metastases, they can still be administered as palliative care. Eloquent areas, physically inaccessible places, and tumors smaller than 3 cm can all be treated with stereotactic radiosurgery. Melanoma The most frequent metastasis linked to cerebral bleeding is metastases.

Also Read: Cerebrovascular Disorders- Clinical Features, Investigations And Treatment

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