#brain tumors

[toriwritesstories]

Life gave me too many fucking lemons...

AKA, just when life was finally starting to really look up for me and my spouse, we found out that they have brain cancer.

Spouse health update in the form of me ranting on Substack 😅

They start chemoradiation in less than a week! Positive thoughts are appreciated 💜

[justkidneying]

Neoplasms of the CNS

This is going to be a long one, so I apologize. This topic can be kinda boring and difficult, but it's good to know for anyone in med school. A lot of this stuff is also pretty high-yield for boards, so yay.

I'm going to go over a lot of different types, give you some basic facts, and show (and tell) you what it looks like. Hope you have a fun time reading :D

Glial Tumors

Glial cells are little helper cells in the brain. Gliomas are tumors made of these cells. You have three subtypes: pilocytic astrocytomas, diffuse low-grade gliomas (low grade astrocytomas and oligodendrogliomas), and malignant gliomas (anaplastic astrocytomas and glioblastomas). Glioblastomas are the most aggressive gliomas.

Pilocytic astrocytomas are the most common primary brain tumor in children. They are well-circumscribed and grow very slowly. They prefer the cerebellum and brainstem. Their most distinguishing feature are the Rosenthal fibers (pilocytic means fiber) and red inclusions. These can usually be treated with resection alone. Look how pretty it is:

Low grade gliomas are the majority of adult brain tumors. They are infiltrating and are WHO grade 2-4. Both diffuse astrocytomas and oligodendrogliomas are going to be basically in the middle of the brain. Oligodendrogliomas prefer white matter of the cerebral hemispheres and infiltrate to the cortex. Microcalcifications are common. Oligodendrogliomas have a "fried egg" and "chickenwire" appearance, but this is usually stated as uniform cells with clear cytoplasm and branching, delicate blood vessels on board exams.

Diffuse astrocytomas show irregular, angulated, and hyperchromatic nuclei, and have a tendency to recur, spread, and progress to higher stages.

Now to the malignant gliomas. Malignant astrocytomas are the most common primary brain tumor in adults. You'll see a hypercellular glioma with poorly differentiated astrocytes. It tends to recue, and shows significant nuclear atypia and miotic activity (it's dividing!!). These can develop from other types of astrocytomas or de novo. They usually progress to glioblastoma.

Glioblastomas are the most common and most malignant gliomas. They are poorly defined, infiltrating, and will distort the brain. Some people say they look like butterflies on MRI (I say these people are full of shit). You'll see serphintine or psuedopalisading necrosis and microvascular proliferation. The morphology of the cells is highly variable (from giant and bizarre to small and tightly packed). There is about a one year median survival from disgnosis.

Medulloblastomas

This is the most malignant brain tumor in children, and is only found in the cerebellum (by definition, obviously). All of them are WHO grade IV. The classic (aka the kind on board exams) is composed of sheets of densly packed cells with round to oval nuclei (or sometimes carrot-shaped lol), and little cytoplasm. They are poorly differentiated and primitive. In 40% of them, there are Homer-Wright (neuroblastic) rosettes (circled below).

Sometimes you see spinal drop metastasis of these, which means the tumor has spread to the spinal cord. This will show up as a "sugar coated" spinal cord on MRI. If the tumor compresses the 4th ventricle, you'll also see increased intracranial pressure.

Ependymomas

These are slow-growing tumors that originate from either the walls of the ventricles or the spinal canal. In kids, they're usually in the brain. In adults, they're usually in the spine. There are like nine subtypes, but the most common feature on histology is perivasuclar psuedorosettes. They have a poor prognosis.

Choroid Plexus Papillomas

These come from the cuboidal cells of the choroid plexus within the ventricles (the things that make CSF). 85% are in kids less than 5 years old, and most are found in the lateral ventricles. They look like cauliflower. Under the microscope, they show papillary structure with delicate fibrovascular cores, with a cuboidal lining. Complete resection is the main treatment.

Neuronal Tumors

We're only gonna talk about gangliocytomas, gangliogliomas, and dysembryoplastic neuroepithelial tumors, but there are other types. Gangliocytomas are the most common tumors associated with chronic temporal lobe epilepsy, but they are rare overall. They show prominent single nucleoli and cytoplasmic basophilic Nissl substance. They also may have pilocytic elements. They may progress to gangliogliomas.

Dysembryoplastic neuroepithelial tumors are low-grade tumors that are seen in kids. Usually they cause seizures. You'll see multinodular lesions in the cortices (usually temporal). Histology looks like prominent clusters of oligodendroglial-like cells, which seem to float in cystic spaces. Resection is the treatment, and usually stops the seizures.

Meningiomas

These are the most common benign tumors in adults, with resection being the primary treatment (unless they're radiation-induced, those fuckers are aggressive). These are attached to the dura mater and compress the brain without invading it. The meningothelial subtype is the only one you need to know the histology of. It has characteristic whorls (can be mineralized) called psammoma bodies. Grossly, they look like an egg yolk.

Primary CNS Lymphomas

PCNSL are usually diffuse large B-call lymphomas. Therefore, they express CD markers. Grossly, they are circumscribed and somewhat necrotic. On histology, they have lymphoid-appearing cells around blood vessels. They're honestly not that interesting in my opinion.

Craniopharyngiomas

These are benign and their origin has to do with some embryology I don't care to explain here. They have neuroendocrine effects, and can usually not be reached for resection, and are therefore considered a lifelong illness. They're usually cystic, solid, and calcified all at once (yum). They are separated into adamantinomatous (kids and adults) and papillary (only in adults). You'll see palisading epithelial cells and wet keratin.

CNS Metastasis

Most common tumor of the CNS, and can occur at any age. Lung cancer is the most common primary tumor. You're going to see edema, and usually they lodge at the gray-white junction. They will be well circumcised and will have histology consistent with the primary lesion.

Peripheral Tumors

We got Schwannomas, Neurofibromas, and Malignant peripheral nerve sheath tumors (MPNSTs). Schwannomas are painless and slow rowing, and just kinda look like a round knot on a nerve. Histologically, they are biphasic, with Antoni A (tight) and Antoni B (loose) areas. You'll also see nuclear palisading with Verocay bodies.

Neurofibromas are either solitary or plexiform. They will present with pain and loss of function. On histology, you'll see myxomatous matric and collagen fibrils leading to intense staining with reticulin.

MPNSTs are highly malignant and aggressive, and are difficult to diagnose. Grossly, you'll see necrosis. Histologically, you'll see hypercellularity, atypia, and pleomorphism.

Neurocutaneous Syndromes

You got neurofibromatosis 1 and 2, tuberous sclerosis, and Von Hippel Lindau disease. With NF1, you have a mutation on chromosome 17, which causes dark skin spots, cutaneous neurofibromas, Lisch nodules on the iris, optic gliomas, seizures, etc.

NF2 is from chromosome 22, and the patient will also sometimes have meningiomas and ependymomas. The biggest thing is bilateral vestibular schwannomas, causing hearing loss, vertigo, and facial weakness. Also common are juvenile cataracts.

Tuberous sclerosis is a disorder of cellular differentiation and proliferation. You'll see ash leaf spots, facial and fingernail angiofibromas, shagreen patches, heart tumors, renal tumor, retinal tumor, lung tumor, epilepsy, etc.

Von Hippel Lindau disease is caused by a deletion on chromosome 3. It is characterized by hemangioblastomas in the retina and CNS. You'll see symptoms from local mass effect and hemorrhage. Patient may also have renal cysts, pheochromocytomas, or pancreatic tumors.

And that's all the ones I want do, I'm not interested in going neuro, so I won't get into the dirty details. They don't really matter unless you want to be a brain surgeon or something.

[cisplus]

Something important I learned about MRIs of the brain is that they have a blind spot.

I've had multiple MRIs of my brain due to concerning symptoms, and each time the MRIs came back perfectly normal. So I believed the doctors who told me that my symptoms were medication-related, and thought I was fine.

Now it turns out that I have a serious illness that's often caused by a brain tumor in the front of the brain. Nobody ever told me that MRIs couldn't see the full brain, or that it was possible to have a normal MRI and still have a brain tumor.

I know that brain tumors are rare, but if anyone else is in a situation like mine, I want you to know about the blind spot that MRIs have, and that your doctor can specifically ask for an MRI that sees the front of the brain.

[er-cryptid]

[mednerds]

Microrobots fight brain tumors in mice

Scientists have created a microrobot that can pass the near-impenetrable blood-brain barrier to treat brain tumors in mice, they report in a new study in Science Robotics.

Researchers at the Harbin Institute of Technology and Harbin Medical University in China were able to combine the natural abilities of neutrophils — bacteria fighting blood cells that can pass through the blood-brain barrier and remain undetected by the immune system — with the powers of magnetic microswimmers. The magnetic particles contained a cancer drug and were coated in E. coli so the neutrophils would consume them. They call these biohybrids “neutrobots,” and found they were effective in keeping mice alive longer than those that were untreated.

While microrobots have long been seen as holding clinical potential, the inability to pass the blood-brain barrier has proved a major hurdle. More work still needs to be done before human patients can benefit from clinical application. Human bodies are much larger than mice and therefore tricker to navigate magnetically. Current imaging systems aren’t able to see or follow neutrobots in real time, but the use of neutrophils for microrobot experiments is still a promising new development.

By Theresa Gaffney and Alex Hogan/STAT 

[kingsbridgelibraryteens]

Reluctant Reader Wednesday: Parenthesis by Elodie Durand

Judith’s life is normal, happy and busy. But sometimes she forgets things, and sometimes she has spells of time that she can’t remember. Her family and friends are worried about her, and she goes to doctors who try to pinpoint her problem. When she learns about what’s really happening inside her brain, the news is devastating. This story is based on the author’s own life, and it packs an emotional punch.

Give this book to teens and adults who love sicklit, autobiographies, and survivor stories.

[leighlim]

People always worry that their headaches are actually brain tumors. I was convinced my brain tumor was actually just a headache.

Geraldine Deruiter

[vulnera-sanentura]

Cat Facts: Brain Tumors

Unlike dogs, cats seem to be fairly resistant to primary neurologic disease. My last two weeks I’ve been on neurology and we’ve seen and treated dozens of dogs for seizures, intervertebral disc disease, meningoencephalitis, and others, but only a single cat the whole time. 

There is the fact that cats tend to hide things more thoroughly than dogs, and still the prevalence of dog owners willing to spend more money on treating their animals than cat owners (though this is evening out compared to the past), but even with these factors cats have significantly less neurologic disease than dogs. They can develop any of the diseases dogs do, however, including... brain tumors.

Warning this is fairly long and pretty dry (hard to make brain tumors joyful so it’s fairly scientific-style writing), but continues under the cut!

Classification: Brain tumors can be either primary or secondary: they can develop from the tissues normally found inside the skull cavity, or metastasize from other places in the body (including other places in the head). I’ll focus on the most common ones instead of overloading with lists of neurologic jargon.

Pathophysiology: Brain tumors generally don’t cause damage from the tumor activity itself, but from compressing the brain as it grows, infiltrating the brain tissue, or obstructing the path of CSF flow. Increase in intercranial pressure, cerebral edema, or hemorrhage can lead to neurologic signs, seizures, herniation of the brain out of the occipital foramen, or acute death.

Clinical Signs: Clinical signs can be chronic, acute, or slowly insidious, ranging from nonspecific to neurologic, with neurologic signs depending on the location of the tumor (forebrain, brainstem, cerebellum, multifocal).

Common signs include:

Behavioral changes

Visual deficits/blindness

Anisocoria (differently sized pupils)

Circling/pacing

Altered mentation

Head pressing

Postural reaction deficits (not knowing where their feet are in space)

Vestibular signs (ataxia, head tilt, nystagmus, loss of balance)

Diagnosis: Presumptive diagnosis can be made by clinical signs localizing the tumor, but CT or MRI can confirm the presence of an intercranial tumor. These imaging diagnostics can tell the location (in the brain, meninges, bone, multifocal) but cannot definitively diagnose the type or grade of tumor. MRI is the diagnostic of choice, but CT can usually visualize tumors and help with surgical planning (3D reconstruction of the skull).

Biopsy and histopathology is required for definitive diagnosis of a specific type of tumor and grading. Metastatic tumors can be diagnosed by biopsying the primary tumor (there’s a chance there’s a second tumor unrelated to the body tumor, but not super likely). Primary brain tumors should be submitted for histopathology at the time of surgery if that is the treatment pursued.

Metastasis checks (radiographs of the thoracic cavity) are recommended before pursuing treatment options, as prognosis decreases when tumors have spread to other parts of the body, as a general rule.

Tumor Types: Meningiomas: the most common type of brain tumor in cats, up to 56-85% of all feline intercranial tumors. These tumors are slow-growing, “benign”, and supratentorial (in the region of the cerebrum).

Benign being in quotes because it’s non-invasive and doesn’t metastasize, though still causes clinical signs and potentially death

Common clinical signs include behavioral changes, ataxia, visual deficits, and seizures

Lymphoma: second most common brain tumor (14%), and can be a primary, solitary tumor a multicentric/diffuse metastasis. If you see intercranial lymphoma, look for it elsewhere as well! Could be the only tumor, but could be more of a systemic disease, as it’s the most common feline tumor.

Pituitary tumors: third most common brain tumor (8%). Can be either adenoma (benign) or carcinoma (malignant). Up to a third of feline pituitary tumors are incidental post-mortem findings. Functional pituitary tumors can cause excessive release of hormones and contribute to acromegaly or Cushings. Nonfunctional ones are more likely to be found post-mortem unless they grow enough to compress the brain.

Others include glial tumors and secondary tumors such as local invasion or metastasis.

Treatment: Surgery: the treatment of choice for feline intracranial meningiomas. Depending on tumor type, size, and location, surgery can be complete excision or debulking to decompress the brain.

There is an approximately 19% mortality rate associated with surgery, though unfortunately I couldn’t find much more information than that.

Chemotherapy: can be added as an additional option post-surgery, or as an alternative to surgery or radiation. Lymphoma is the most responsive to chemotherapy.

Radiation: good for non-surgical cases (money, invasive/diffuse disease, etc). Especially used in pituitary tumors, and lymphoma is also radiation-responsive.

Prognosis: Post-surgical median survival time for cats with meningiomas is reported as good at >2 years with recurrence being uncommon. Cats with meningiomas that do not undergo surgery usually lived 3-6 months.

Intercranial lymphoma has a poorer prognosis, with a MST of <70 days.

Pituitary tumors treated with radiation therapy have an MST of 17 months, while if untreated it drops down to 50 days.