What is leptomeninges in anatomy?
leptomeninges [lep′tōminin′jēz] the arachnoid membrane and the pia mater, two of the three layers covering the brain and spinal cord.
What are leptomeninges and pia mater?
leptomeninges [lep′tōminin′jēz] the arachnoid membrane and the pia mater, two of the three layers covering the brain and spinal cord. Compare meninges.
What is leptomeningeal meningitis?
The term leptomeningeal (from the Greek lepto, meaning “fine” or “slight”) describes the thin meninges, the arachnoid and the pia mater, between which the cerebrospinal fluid is located. The disorder was originally reported by Eberth in 1870.
What is a leptomeningeal Metastase?
Unlike the spread of cancer to the brain itself (brain metastases), leptomeningeal metastases involve the spread of cancer cells to the cerebrospinal fluid that bathes the brain and spinal cord. It arises due to the seeding of cancer cells into the leptomeninges, the two innermost layers of the meninges that cover and protect the brain.
Where are leptomeninges located?
the brainTHE LEPTOMENINGES The arachnoid is attached to the overlying dura mater. It consists of several layers of translucent cells that follow with the dura and a contingent of cells that form spindly trabeculae that bridge the subjacent space and attach to the pia mater on the surface of the brain.
Where are the 3 meninges found?
Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater.
Where are the cranial meninges located?
the brainThe cranial meninges (singular: meninx) surround the brain and are made up of three layers (from outermost to innermost): dura mater. arachnoid mater. pia mater.
What is the difference between meninges and leptomeninges?
Meninges are membranes that cover the spinal cord and nerve roots. The outer membrane is a tough, thick, fibrous structure called the dura mater, to the outer side of which is the epidural space. The inner membranes are more delicate and are termed the leptomeninges.
What are the main functions of meninges?
The meninges: Protect your CNS (central nervous system) from trauma injury to your brain, such as a blow to your head by acting as a shock absorber. They anchor your CNS and keep your brain from moving around within your skull.
How do you remember the meninges of the brain?
A crafty way of remembering the meninges of the brain is by using the mnemonic PAD; Pia, Arachnoid, Dura. Remember the meninges pad the brain, protecting it.
Which of the meninges is located next to the brain?
Dura Mater The outermost mater of the meninges, the dura, is composed of two layers: the periosteal layer that lies closest to the calvarium and the meningeal layer that lies closest to the brain tissue.
What is the difference between cranial and spinal meninges?
Furthermore, cranial meninges contain two layers in the dura mater while the spinal meninges contain a single layer in the dura mater. In addition, cranial meninges may not produce an epidural space while spinal meninges produce an epidural space filled with fat.
What is between the brain and skull?
Between the skull and brain is the meninges, which consist of three layers of tissue that cover and protect the brain and spinal cord. From the outermost layer inward they are: the dura mater, arachnoid and pia mater.
What are the leptomeninges?
The leptomeninges are the inner part of your meninges (the three layers of membrane that cover and protect your brain and spinal cord). Cerebrospinal fluid is the clear fluid produced by your brain that surrounds your entire central nervous system and has direct contact with your leptomeninges.
How common is leptomeningeal disease?
Although only 5% of patients with breast cancer develop leptomeningeal involvement, it remains the most common etiology of LMD [12]. The second most common tumor with LMD is lung cancer. Rare neoplasms, such as retinoblastoma and embryonal rhabdomyosarcoma, can also spread to leptomeninges.
What are the three meninges and two named spaces that surround the brain in order from superficial to deep outermost to innermost )?
The term meninges comes from the Greek for "membrane" and refers to the three membranes that surround the brain and spinal cord. The membrane layers (discussed in detail below) from the outside in are the: dura mater, arachnoid mater, and pia mater.
Which of the meninges is located next to the brain?
Dura Mater The outermost mater of the meninges, the dura, is composed of two layers: the periosteal layer that lies closest to the calvarium and the meningeal layer that lies closest to the brain tissue.
What are the 3 parts of the brain?
The brain can be divided into three basic units: the forebrain, the midbrain, and the hindbrain. The hindbrain includes the upper part of the spinal cord, the brain stem, and a wrinkled ball of tissue called the cerebellum. The hindbrain controls the body's vital functions such as respiration and heart rate.
Where is the dura mater?
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. The other two meningeal layers are the arachnoid mater and the pia mater.
Where is cerebrospinal fluid found?
Cerebrospinal fluid (CSF) is a clear, colorless, watery fluid that flows in and around your brain and spinal cord. Your brain and spinal cord make up your central nervous system.
What is the name of the mater of a leptomeninge?
Leptomeninges (singular: leptomeninx) comprise both the arachnoid mater and the pia mater. This term is usually used in association with the term pachymeninx, a synonymous term for the dura mater.
Where does the term "leptomeninx" come from?
Leptomeninx comes from the Ancient Greek 'leptos' meaning thin and 'meninx' meaning membrane.
What is the name of the mater of a leptomeninge?from radiopaedia.org
Leptomeninges (singular: leptomeninx) comprise both the arachnoid mater and the pia mater. This term is usually used in association with the term pachymeninx, a synonymous term for the dura mater.
Where does the term "leptomeninx" come from?from radiopaedia.org
Leptomeninx comes from the Ancient Greek 'leptos' meaning thin and 'meninx' meaning membrane.
What are the two layers of the meninges?from medical-dictionary.thefreedictionary.com
the tough pachymeninx or dura mater), considered together; by this concept, the arachnoid and pia are two parts of a single layer, much like the parietal and visceral layers of a membrane or bursa; although separated by the subarachnoid space they are connected via the arachnoid trabeculae and become continuous where the nerves and filum terminale exit the subarachnoid space (the cerebrospinal fluid-filled space bounded by the leptomeninges).
What is the meningeal component of cryptococcal infection?from medical-dictionary.thefreedictionary.com
In our patient, it appeared that the meningeal component of the Cryptococcal infection involved the perivascular spaces at the base of the brain and cerebellar leptomeninges. On magnetic resonance (MR), there was a focal hyperintensity, with abnormal restricted diffusion indicating acute insult.
Which part of the brain has diffuse infiltrates?from medical-dictionary.thefreedictionary.com
Brain; Cerebral cortex (arrow head) and Leptomeninges(black arrow) with a diffuse infiltrate of maligrant cells.
Where is metastatic spread seen?from medical-dictionary.thefreedictionary.com
The metastatic spread is seen only in the leptomeninges. MRI; FLAIR (a); FSE/T2WI (b); SE/T1WI after gadolinium administration (c, d); DWI (e); ADC map (f).
Diagnosis and Tests
Healthcare providers diagnose leptomeningeal disease with magnetic resonance imaging (MRI) of your brain and/or spine, as well as performing a spinal tap (lumbar puncture) to obtain cerebrospinal fluid that they can examine for the signs and presence of cancer cells.
Management and Treatment
Unfortunately, healthcare providers aren’t able to cure this condition. Instead, they focus on ways of slowing down the spread of cancer and easing symptoms. Treatments vary based on the kind of cancer that spread to your cerebrospinal fluid and leptomeninges, where the cancer is located and your overall health. Some common treatments include:
Prevention
Unfortunately, there aren’t any ways to reduce the risk of leptomeningeal disease.
Living With
If you have leptomeningeal disease, it’s important that you have a clear view of your prognosis. Leptomeningeal disease is a serious complication of advanced or late-stage cancer and can’t be cured. Ask your healthcare provider what you can expect, given your specific situation.
Which two delicate layers of the meninges are considered together?
The two delicate layers of the meninges, the arachnoid mater and pia mater considered together.
What are the two layers of the meninges?
the tough pachymeninx or dura mater), considered together; by this concept, the arachnoid and pia are two parts of a single layer, much like the parietal and visceral layers of a membrane or bursa; although separated by the subarachnoid space they are connected via the arachnoid trabeculae and become continuous where the nerves and filum terminale exit the subarachnoid space (the cerebrospinal fluid-filled space bounded by the leptomeninges).
What is the meningeal component of cryptococcal infection?
In our patient, it appeared that the meningeal component of the Cryptococcal infection involved the perivascular spaces at the base of the brain and cerebellar leptomeninges. On magnetic resonance (MR), there was a focal hyperintensity, with abnormal restricted diffusion indicating acute insult.
Where is metastatic spread seen?
The metastatic spread is seen only in the leptomeninges. MRI; FLAIR (a); FSE/T2WI (b); SE/T1WI after gadolinium administration (c, d); DWI (e); ADC map (f).
Is leptomeningeal glioneuronal tumor misdiagnosed?
A Case of Diffuse Leptomeningeal Glioneuronal Tumor Misdiagnosed as Chronic Tuberculous Meningitis without Brain Biopsy
What is the leptomeninge?
Leptomeninges. The leptomeninges are formed by the arachnoid and pia. The arachnoid is loosely attached to the dural border cell layer. Pathologies often affect both the arachnoid and dura together, and the 2 areas cannot be easily differentiated on imaging.
What is the most common site of meningeal syndrome?
In fact, few such patients have a typical meningeal syndrome. They are usually alert, and without neck stiffness. The meninges at the bases of skull and cord are the most frequent sites of involvement. The usual clinical syndrome is that of mononeuritis multiplex, due to entrapment of nerve roots by meningeal growth.
Where are pial cells located?
Pial cells form a delicate membrane intimately attached to the neural surface, surrounding vessels located in the subarachnoid space and interconnecting with the arachnoid trabecular cells. Spinal pial cells contribute to the formation of the denticulate ligaments, located on the lateral surface of the cord, halfway between the dorsal and ventral roots and extending laterally to the inner surface of the spinal dura. In likewise manner, the filum terminale arises from the conus medullaris, has a core of pial cells and an arachnoid cells covering, and transverses the subarachnoid space of the lumbar cistern to attach to the inner surface of the caudal extreme of the dural sac.
What is the term for the pia mater and arachnoid?
THE LEPTOMENINGES. Leptomeninx is the term used when the pia mater and arachnoid are considered together as a functional unit and contraposed to pachymeninx (from the Greek packys, meaning thick), designates the finer meningeal coverings. 2. The arachnoid is attached to the overlying dura mater.
Why do cryptococci elicit little inflammation?
Typically inconspicuous in H&E sections , pale-staining cryptococci usually elicit little inflammation due to the immunocompromised status of the host.
Where are Cryptococcus found?
Cryptococcus species, usually found extracellularly in the subarachnoid or perivascular spaces , are gray-blue in H&E sections. Some organisms are ingested by macrophages .
Is leptomeninges congested?
Leptomeninges become congested, diffusely hyperaemic with limited infiltration and focal demyelination in spinal cord and white matter of the brain has been observed (Viriyavejakul et al., 1997).
Why is leptomeningeal disease so challenging?
Diagnosing leptomeningeal disease can be challenging, not only because of the overlap of symptoms with those of brain metastases, but because of the testing process. A high index of suspicion is necessary to ensure that the appropriate tests are run for a timely diagnosis.
Why is leptomeningeal disease so difficult to diagnose?
Diagnosis. Diagnosing leptomeningeal disease can be challenging, not only because of the overlap of symptoms with those of brain metastases, but because of the testing process. A high index of suspicion is necessary to ensure that the appropriate tests are run for a timely diagnosis.
Why are leptomeningeal metastases so difficult to treat?
Leptomeningeal metastases are challenging to treat for several reasons. One is that they often occur in advanced stages of cancer and after a person has been ill for a significant period. For this reason, people with the disease may be less able to tolerate treatments such as chemotherapy.
How long do you live with leptomeningeal metastases?
In general, the prognosis of leptomeningeal metastases is poor, with life expectancy often measured in months or weeks. That said, some people who are otherwise in reasonable health and can tolerate treatments do very well. This number of longer-term survivors living with leptomeningeal disease is expected to grow now that newer treatments that can penetrate the blood-brain barrier are available.
What is the diagnosis of leptomeningeal disease?
Diagnosis is usually made with a combination of an MRI and spinal tap. Treatments may include radiation and/or chemotherapy directly into the spinal fluid (intrathecal chemotherapy), along with systemic treatments for the particular cancer being treated.
What is the term for the spread of cancer cells to the brain?
Anatomy. Unlike the spread of cancer to the brain itself (brain metastases), leptomeningeal metastases involve the spread of cancer cells to the cerebrospinal fluid that bathes the brain and spinal cord. It arises due to the seeding of cancer cells into the leptomeninges, the two innermost layers of the meninges that cover and protect the brain.
Where is the intrathecal chemo placed?
Intrathecal chemotherapy was once administered via a spinal tap needle. Today, surgeons usually place an Ommaya reservoir ( an intraventricular catheter system) under the scalp, with the catheter traveling into the cerebrospinal fluid. This reservoir is left in place for the duration of chemotherapy treatment.
Why is leptomeningeal disease becoming more evident?
Leptomeningeal disease is becoming more evident because cancer patients are living longer and many chemotherapies cannot reach sufficient concentrations in the spinal fluid to kill the tumor cells.
How many cases of leptomeningeal cancer are there in the US?
In the United States, 1–8% of cancer patients are diagnosed with leptomeningeal disease, with approximately 110,000 cases per year. The exact incidence of leptomeningeal disease is difficult to determine, since gross examination at autopsy may overlook signs of leptomeningeal disease, and microscopic pathological inspection may be normal if the seeding is multifocal or if an unaffected area of the central nervous system (CNS) is examined.
What is the term for the disease that spreads from the original tumor site to the meninges surrounding the brain?
Leptomeningeal cancer (also called leptomeningeal carcinomatosis, leptomeningeal disease (LMD), leptomeningeal metastasis, neoplastic meningitis, meningeal metastasis and meningeal carcinomatosis) is a rare complication of cancer in which the disease spreads from the original tumor site to the meninges surrounding the brain and spinal cord. This leads to an inflammatory response, hence the alternative names neoplastic meningitis (NM), malignant meningitis, or carcinomatous meningitis. The term leptomeningeal (from the Greek lepto, meaning 'fine' or 'slight') describes the thin meninges, the arachnoid and the pia mater, between which the cerebrospinal fluid is located. The disorder was originally reported by Eberth in 1870.
Can meninges have a single cell layer?
Second, there may only be a thin coating of meninges, in some cases with only a single cell layer, but also with shedding of tumor cells into the cerebrospinal fluid. Third, there may be a pattern of nodular deposits of tumor on cranial and spinal nerve roots, frequently without tumor cells being shed into the cerebrospinal fluid .
Which pattern of tumors is most common in solid tumors?
The first and third patterns are common in solid tumors whereas the second occurs most frequently with leukemia and lymphoma.
Can you get a leptomeningeal tumor while receiving chemotherapy?
Some patients can develop a leptomeningeal tumor while receiving chemotherapy for their primary tumor.
Where are meninges found?from study.com
The meninges are also found in the spinal cord. Each layer is observed in the cross section.
What is the meninges?from thoughtco.com
Updated July 02, 2019. The meninges is a layered unit of membranous connective tissue that covers the brain and spinal cord. These coverings encase central nervous system structures so that they are not in direct contact with the bones of the spinal column or skull.
What is the thinnest meninge of the brain?from study.com
The pia mater , which translates to "tender matter," is the thinnest and deepest meninge of the brain. This thin, clear layer adheres to the surface of the brain and follows the natural hills and valleys (called gyri and hillocks) of the surface of the brain. The pia mater functions to contain cerebrospinal fluid within its proper pathway. Additionally, about 30% of the total CSF is produced by the pia mater .
What are the three membranes of the meninges?from thoughtco.com
The meninges are composed of three membrane layers known as the dura mater, arachnoid mater, and pia mater . Each layer of the meninges serves a vital role in the proper maintenance and function of the central nervous system.
What would happen if the spinal cord was not connected to the meninges?from study.com
Without the meninges, the spinal cord and brain would be subject to much more trauma. The meninges provide safety and security to the central nervous system.
How many layers are there in the meninges?from thoughtco.com
The meninges can be generally separated into three distinct layers, each with its own specific function and traits.
Which layer of the spinal column is composed of the meningeal layer and does not contain a perio?from thoughtco.com
The dura mater of the spinal column is composed of the meningeal layer and does not contain a periosteal layer. Arachnoid Mater: This middle layer of the meninges connects the dura mater and pia mater. The arachnoid membrane loosely covers the brain and spinal cord and gets its name from its web-like appearance.
What is the path of leptomeninges?
The anatomic route taken by malignant cells to seed the leptomeninges may include spread from the brain parenchyma,6,24choroid plexus, blood,6,7or cerebrospinal fluid (CSF) after surgical resection25,26(Fig. 1). The blood-brain barrier (BBB) frequently blocks otherwise effective systemic therapies, creating a pharmacologically protected space for tumor cells to proliferate once they seed the leptomeninges. Once LMC develops, tumor growth can lead to cranial nerve dysfunction, inflammation, and hydrocephalus. Circulation of the blood and/or CSF frequently leads to the spread of metastatic cells resulting in multifocal CNS disease.5,6The diffuse nature of LMC combined with the relative inaccessibility of the brain to treatment contributes to the severe morbidity and rapid mortality observed in patients with LMC.
What are the properties of leptomeningeal membranes?
Similar to the metastatic microenvironment in other areas of the body, the leptomeningeal membranes possess a rich ecosystem of vasculature, fibroblasts , infiltrating immune cells, and extracellular matrix.27As such, metastatic disease progression at this site is likely a combination of cell intrinsic (eg, gene expression, metabolism, glycosylation) and cell extrinsic (eg, brain microenvironment) factors. Despite advances in the cellular and genetic characterization of primary cancers, the underlying molecular alterations that enable leptomeningeal spread remain poorly understood. Malignant metastatic cells from different primary sites likely have shared properties that allow survival in the leptomeninges.5Such properties may include anoikis and immune system evasion as cancer cells travel through the blood and CSF, tissue invasion through epithelial cells in the choroid plexus and parenchyma, and angiogenesis required for thriving within the leptomeninges.28In 1 study, analysis of lung cancer primary tumors and matched leptomeningeal metastases using next-generation sequencing revealed a high degree of genetic divergence and clonal heterogeneity between the paired samples.29A variety of potential sources may underlie this genetic divergence, such as mutations acquired during metastasis formation or in response to pressures from the leptomeningeal microenvironment. However, it is also possible that some of the genetic divergence observed is due to clonal evolution of a subset of cells in the primary tumor predisposed to metastasize to the leptomeninges. In line with this, studies have shown that the leptomeninges upregulate stromal derived factor-1 alpha and vascular endothelial growth factor, which hone tumor cells to the CNS and increase blood supply to metastatic tumors, respectively, suggesting that the leptomeninges may inadvertently support LMC progression.30–32
What is the term for the spread of cancer to the pia mater, arachnoid, and sub?
Leptomeningeal carcinomatosis (LMC), also known as leptomeningeal metastasis or leptomeningeal disease, is the metastatic spread of cancer to the pia mater, arachnoid, and subarachnoid space.1LMC occurs in 5% to 15% of patients with cancer, has limited therapeutic options, and has an average survival time of 2 to 6 months.1–6LMC most commonly arises as a result of metastasis from primary cancers originating outside the central nervous system (CNS), but LMC can also arise from primary CNS tumors, including astrocytomas, medulloblastomas, and ependy-momas.7The incidence of LMC continues to steadily increase across primary tumor types, likely because of more sensitive detection methods and improved efficacy of therapeutics able to control systemic disease.1,8Currently, whole brain or cranial-spinal radiation and intrathecal (IT) or systemic chemotherapy have offered limited survival benefit with substantial risks of treatment-related toxicity.5,9Thus, the need for a more comprehensive characterization of disease pathogenesis in order to identify novel therapeutic targets has become increasingly urgent. Although recent scientific advances have increased the understanding of how malignant cells seed and thrive within the leptomeninges, more studies are still required. In this review, the authors summarize their current understanding of the molecular landscape of LMC, outline clinical management of these patients, and highlight emerging therapeutic options.
What percentage of cancers metastasize to leptomeninges?
Nearly every primary tumor type has been reported to metastasize to the leptomeninges. Approximately 5% to 8% of solid tumors and 5% to 15% of hematologic malignancies metastasize to the leptomeninges. The most common cancers that give rise to LMC are lung (9%–25%), breast (5%–8%), melanoma (6%–18%), acute lymphoblastic leukemia (1%–10%), and non-Hodgkin lymphoma (5%–10%).4–6,10–15The incidence of LMC also varies based on the molecular and/or histologic subtypes of the primary cancer, as seen in breast and lung groups. For example, in a study of 118 patients with breast LMC, 35% of patients had breast tumors that exhibited lobular histology.16Considering that only 10% of all primary breast cancers are invasive lobular carcinoma, there is a clear overrepresentation of this histologic subgroup in LMC.17In addition, the triple-negative molecular subtype of breast cancer (TNBC) comprises roughly 40% of breast LMC cases, although TNBC accounts for only 10% of all diagnosed breast cancers.16,18TNBC patients are at 4 times higher risk of developing LMC compared with patients with hormone receptor positive and HER2+breast cancer.19With respect to lung cancer, patients with non–small cell lung cancer (NSCLC), specifically those with epidermal growth factor receptor (EGFR)-mutant disease, are more than 3 times as likely to develop LMC as compared with those with EGFR-wild-type tumors.20,21Given difficulties in diagnosis and rapid mortality, these rates are likely underestimates of the true incidence of LMC.1In fact, 1 postmortem analysis of patients with cancer that exhibited neurologic symptoms revealed that 18% had evidence of leptomeningeal infiltration.20
How are rodent models of LMC established?
Rodent models of LMC are most commonly established through injection of cancer cells directly into the cisterna magna, or into the subarachnoid space of the spinal cord.33,56,57The authors’ laboratory has recently demonstrated that injection of cancer cells into the internal carotid artery of mice, a technique previously described as a method to recapitulate brain metastasis in mice, also leads to the formation of LMC (Chernikova et al., under review). Using this technique, the authors model TNBC LMC and show improvements in survival following treatment with the chemotherapeutic Cyclophosphamide, or a novel, brain penetrant chemotherapeutic QBS10072S. Using a mouse model of lung LMC to investigate mechanisms of resistance to Gefitinib, Nanjo and colleagues58found that copy number gain of the MET oncogene, and its subsequent activation, is implicated in the development of drug resistance. In a similarly themed study seeking to elucidate mechanisms of ALK-tyrosine kinase inhibitors (TKI) resistance in lung LMC, Arai and colleagues59found that decreased expression of microRNA-449a led to overexpression of amphiregulin (a ligand of EGFR) and subsequent EGFR activation, regulating the development of resistance to the ALK-TKI Alectinib. AZD3759, a BBB-penetrant EGFR inhibitor, has demonstrated tumor regression in a mouse model of lung LMC,56with clinical trials currently underway [{"type":"clinical-trial","attrs":{"text":"NCT02228369","term_id":"NCT02228369"}}NCT02228369]. Not only have animal models deepened the understanding of LMC formation and progression but they have also enabled preclinical testing of promising therapies.
How long does melanoma LMC last?
In a study of patients with melanoma LMC, the median survival of 10 patients treated with Ipilimumab, a monoclonal antibody against CTLA-4, was 15.8 weeks.98In comparison, the median survival of patients receiving any treatment was 16.9 weeks, demonstrating no improvement with Ipilimumab. A study of 42 patients with melanoma LMC treated with IT interleukin-2 (IL-2) found median OS among these patients to be 9.1 months with greater than 16% surviving more than 24 months.99This improvement is notable over a median survival of roughly 2 to 6 months among patients with any form of treatment.1This finding was corroborated by another study of patients with melanoma LMC, in which patients who received IT administration of IL-2 had remarkably increased survival time (7.8 months) compared with patients who did not (1.6 months).100
