Walter Dandy

Walter Edward Dandy (April 6, 1886-April 19, 1946) was an American neurosurgeon. He is considered as one of the founding fathers of modern neurosurgery.

After graduation Dandy became the sixth appointee to the Hunterian Laboratory of Experimental Medicine under Harvey W. Cushing from 1910-1911. In 1911, he earned a Master of Arts degree for his work in the Hunterian Laboratory, and went on to join the Johns Hopkins Hospital surgical house staff for one year as Cushing's Assistant Resident (1911-1912). Dandy completed his general surgery residency at the Johns Hopkins Hospital under William S. Halsted in 1918. While Dandy was introduced to the nascent field of neurosurgery by Cushing, it was George J. Heuer who completed Dandy's neurosurgical training after Cushing's departure for the Peter Bent Brigham Hospital in Boston in September 1912. Heuer had graduated from the Johns Hopkins University School of Medicine , worked as Cushing's first Assistant Resident  and served as Halsted's Chief Resident.

One of the earliest products of the Hunterian experience was Walter Dandy. During the two years after medical school, Dandy completed his monumental work on cerebrospinal fluid production, judged by many to be the finest piece of surgical research ever accomplished. While still a house officer, he devised pneumo-encephalography, which was the basis of neurological imaging for nearly 50 years. Dandy went on the be the most famous surgeon of his generation and the greatest technician the field has known. His innovations introduced surgery for disc disease, surgery for aneurysms and arteriovenous malformations as well as surgery for functional disease. The modern scope of neurosurgery was encompassed by Dandy.

Dandy joined the staff of the Johns Hopkins Hospital in 1918 and immediately focused his energies on the surgical treatment of disorders of the brain and spinal cord. When Heuer left Hopkins in 1922 to become the head of surgery at the University of Cinicinnati, Dandy remained as the only neurosurgeon at the Johns Hopkins Hospital until his death in that hospital in 1946.

Dandy is credited with numerous neurosurgical discoveries and innovations, including the description of the circulation of CSF in the brain, surgical treatment of hydrocephalus, the innovation of air ventriculography & pneumoencephalography, the description of brain endoscopy, the establishment of first intensive care unit and first clipping of an intracranial aneurysm.

Walter Dandy trained under Cushing at John Hopkins Hospital. Dandy made a number important contributions to neurosurgery. Dandy developed the technique of pneumoencephalography and provided the neurosurgeon the opportunity to localize a brain tumor by analyzing the displacement of air in the ventricles.

Dandy was an innovative neurosurgeon, considerably more aggressive in style and technique than Cushing.

Dandy was first to show that acoustic neuroma could be removed in totality.

In 1913 and 1914, Dandy and Kenneth D. Blackfan published two landmark papers on the production, circulation, and absorption of CSF in the brain and on the causes and potential treatments of hydrocephalus. Hydrocephalus is the buildup of CSF within the brain, an often lethal condition if left untreated. They described two forms of hydrocephalus, namely "obstructive" and "communicating," thus establishing a theoretical framework for the rational treatment of this condition.

He first introduced the technique ablating and removing the choroid plexus to reduce the production of CSF  for treating hydrocephalus.

In 1921 Dandy reported a case of hydrocephalus caused by obstruction of outflow of CSF from the fourth ventricle. In 1944 A. Earl Walker (who eventually became chairman of neurosurgery at Johns Hopkins) described a similar case of congenital closure of the outflow of the fourth ventricle. This congenital anomaly became known as the Dandy-Walker cyst. It is associated with closure of the foramina of Luschka and Magendie (the outflow openings of the fourth ventricle), atrophy of the cerebellum and cerebellar vermis, dilation of the fourth ventricle, hydrocephalus, and often atrophy of the corpus callosum.

Dandy was among the first to surgically deal with cerebral aneurysms by obliterating them with snare ligatures or metal clips.

Dandy's surgical innovations proceeded at an astounding rate as he became increasingly comfortable operating on the brain and spinal cord. He described in 1921 an operation for the removal of tumors of the pineal region, in 1922 complete removal of tumors of the cerebellopontine angle (namely acoustic neuromas), in 1922 the use of endoscopy for the treatment of hydrocephalus ("cerebral ventriculoscopy"), in 1925 sectioning the trigeminal nerve at the brainstem to treat trigeminal neuralgia, in 1928 treatment of Ménière's disease (recurrent vertiginous dizziness) by sectioning the vestibular nerves, in 1929 removal of a herniated disc in the spine, in 1930 treatment of spasmodic torticollis, in 1933 removal of the entire cerebral hemisphere ("hemispherectomy") for the treatment of malignant tumors, in 1933 removal of deep tumors within the ventricular system, in 1935 treatment of carotid-cavernous fistulas (CCFs), in 1938 ligation or "clipping" of an intracranial aneurysm, and in 1941 removal of orbital tumors.

Walter Dandy’s many contributions have earned him a prominent place in the annals of neurological surgery.

Sources:

Wikipedia

http://www.hopkinsmedicine.org/neurology_neurosurgery

The society of Neurological Surgeons

Youmans Neurological Surgery ( H. Richard Winn)

Harvey Williams Cushing

Harvey Williams Cushing (April 8, 1869 – October 7, 1939)  is often called the "father of modern neurosurgery." He was the founder of American neurosurgery.

He studied medicine at Harvard Medical School at received degree in 1895. He did residency in surgery under the guidance of  famous surgeon , William  Halsted at John Hopkins Hospital, Baltimore. Cushing learned meticulous surgical technique from his mentor. As was standard then, Cushing spent time in Europe ; he worked in the laboratories of Theodore Kocher in Bern, where he investigated the physiology of CSF. He described Cushing reflex, relationship between blood pressure and intracranial pressure.

While traveling through Europe , he met several important surgical personalities , including Victor Horsley.  

The specialty of neurosurgery was born at Johns Hopkins. In 1900, Harvey Cushing completed his surgical training. After the European grand tour and a year in Kocher's laboratory in Bern where he studied the effects of head injury, Cushing returned to the surgical faculty. In the ensuing 12 years, he founded the specialty of neurosurgery and established the characteristics of the field which endure to this day.
By the time Cushing accepted the Harvard Chair of surgery in 1912, his work at Johns Hopkins had established him as the outstanding young surgeon in the United States. Cushing brought Halsted's meticulous surgical technique to the new field and added Osler's careful clinical observation and his own penchant for accurate documentation. His clinical contributions are legendary: the use of x-rays in surgical practice, physiological saline for irrigation during surgery, understanding the pituitary's function, founding the clinical specialty of endocrinology, the anesthesia record, the use of blood pressure measurement in surgical practice, and the physiological consequences of increased intracranial pressure.

One of the principal inducements for Cushing to stay in Baltimore upon completion of his residency was his appointment as Director of the Hunterian Laboratory. Our concept of the clinician/scientist in medicine largely derives from Cushing's vision of the Hunterian as a place for young physicians to learn to do research.One of the earliest products of the Hunterian experience was Walter Dandy.

He described endocrine syndrome due to basophilic adenoma of pituitary gland ( Cushing disease).

With Percival Bailey in 1926, Cushing introduced the first rational approach to the classification of brain tumors.

At age of 32 , he became associate professor of surgery at John Hopkins Hospital and was in full charge of cases of surgery of the central nervous system.

He made (with Kocher) a study of ICP and (with Sherrington) contributed much to the localization of the cerebral centers.

In 1911, he was appointed surgeon-in-chief at Peter Bent Brigham Hospital in Boston. He became a professor of surgery at the Harvard Medical School starting in 1912. From 1933 to 1937, when he retired, he worked at Yale University School of Medicine.

In the beginning of the 20th century he developed many of the basic surgical techniques for operating on the brain. This established him as one of the foremost leaders and experts in the field. Under his influence neurosurgery became a new and autonomous surgical discipline.

He considerably improved the survival of patients after difficult brain operations for intracranial tumors. He used x-rays to diagnose brain tumors. He used electrical stimuli for study of the human sensory cortex. He had operated more than 2000 cases brain tumors.

Cushing was also awarded the Pulitzer Prize of biography in 1926 for a book recounting the life of one of the fathers of modern medicine, Sir William Osler.

He developed many surgical instruments that are still in use today, most notably the Cushing forceps, He also developed a surgical magnet while working with the Harvard Medical Unit in France during World War I to extract bullets from the heads of wounded soldiers.

Sources: Wikipedia
               Y. Neurological surgery  ( H.R. Winn ) Elsevier Saunders
              http://www.hopkinsmedicine.org/neurology_neurosurgery

Sir Victor Horsley: Pioneer of neurological surgery

 

 

Sir Victor Horsley was the first physician to remove a spinal tumor, in 1887, by means of a laminectomy. He developed many practical neurosurgical techniques, including the hemostatic bone wax, the skin flap, the ligation of the carotid artery to treat cerebral aneurysms, the transcranial approach to the pituitary gland and the intradural division of the trigeminal nerve root for the surgical treatment of trigeminal neuralgia.

As a neuroscientist, he carried out studies of the functions of the brain in animals and humans, particularly on the cerebral cortex. His studies on motor response to faradic electrical stimulation of the cerebral cortex, internal capsule and spinal cord became classics of the field. These studies were later translated to his pioneering work in the neurosurgery for epilepsy. Horsley was also the first to use intraoperative electrical stimulation of the cortex for the localization of epileptic foci in humans, between 1884 and 1886.

His best known innovation is the Horsley–Clarke apparatus (developed together with Robert H. Clarke in 1908) for performing the so-called stereotactic neurosurgery, whereby a set of precise numerical coordinates are used to locate each brain structure.

Source: Wikipedia 

Immortalized in surgical history for the introduction of "antiseptic wax," Sir Victor Horsley played a pivotal role in shaping the face of standard neurosurgical practice. His contributions include the first laminectomy for spinal neoplasm, the first carotid ligation for cerebral aneurysm, the curved skin flap, the transcranial approach to the pituitary gland, intradural division of the trigeminal nerve root for trigeminal neuralgia, and surface marking of the cerebral cortex. A tireless scientist, he was a significant player in discovering the cure for myxedema, the eradication of rabies from England, and the invention of the Horsley-Clarke stereotactic frame. As a pathologist, Horsley performed research on bacteria and edema and founded the Journal of Pathology. Horsley's kindness, humility, and generous spirit endeared him to patients, colleagues, and students. Born to privilege, he was nonetheless dedicated to improving the lot of the common man and directed his efforts toward the suffrage of women, medical reform, and free health care for the working class. Knighted in 1902 for his many contributions to medicine, Sir Victor met an untimely death during World War I from heat stroke at the age of 59. An iconoclast of keen intellect, unlimited energy, and consummate skill, his life and work justify his epitaph as a "pioneer of neurological surgery."

Reference: Tan TC, Black PM. Sir Victor Horsley (1857-1916): pioneer of neurological surgery .Neurosurgery. 2002 Mar;50(3):607-11; discussion 611-2.

 

 

CNS complications in HIV infection (AIDS)

Neurologic complications occur in more than 40% of patients with HIV infection. They are the presenting features of AIDS in 10-20% of cases.¹

The access to the AIDS treatment has improved leading to decreased mortality in last decade but the spread of infection is still high.

Types of CNS complications 

Brain may be affected by a variety of abnormalities in association with HIV infection. . Opportunistic infections depend upon the clinical stage of the disease, viral load and CD4⁺ Lymphocyte count.

AIDS patients are more prone for vasculitis causing stroke leading to Transient Ischemic Attack ( TIA) , infarct and hemorrhages in brain and  vascular myelopathy.

HIV- associated neurocognitive disorder

HIV encephalitis also called AIDS- dementia complex ( ADC ) , is a progressive subcortical dementia.

CNS Lymphoma

Progressive Multifocal Leukoencephalopathy ( PML)

Fungal Infections ( e.g. Cryptococcal meningitis)

Tubercular meningitis,  Toxoplasmosis, Neurocysticercosis, Cytomegalovirus ( CMV) encephalitis

Kaposi Sarcoma , Peripheral neuropathies

DIAGNOSIS

To diagnose CNS involvement in AIDS , CT scan or MRI with contrast with MR spectroscopy is very useful tool . Other investigations like CSF study and stereotactic biopsy are needed depending upon the type of involvement.

Sources:
Medscape http://www.emedicineheath.com

http://www.who.int/topics/hiv_aids

http://www.nhs.uk/conditions/hiv

http://www.theglobalfund.org

http://www.dirjournal.org/pdf ( Diag Interv Radiol 2010; 16:193-200)

http://www.oici.org

RED

http://en.wikipedia.org/wiki/HIV/AIDS

http://aidsinfo.nih.gov

Google search

CNS Infections

Brain abscess
Pyogenic brain abscess is a focal collection of pus within the brain. It is initiated when bacteria gain entry into cerebral tissues with trauma, contiguous spread from a suppurative focus (in middle ear, oropharynx, & paranasal sinuses), or hematogenous dissemination from a distant infection.

Subdural empyema
pus collection in subural space. The pathogenesis of subdural empyema is similar to brain abscess.

Epidural Abscess

Osteomyelitis ( Post operative, Post Traumatic, Tubercular, Pyogenic , etc.)

Post craniotomy infections

Meningitis
      Bacterial, Viral, Fungal, Tubercular

Vertebral osteomyelitis

Spinal epidural abscess

Granulomas ( Neurocysticercosis, tubercular)

Toxoplasmosis, HIV infection ( AIDS)

Blastomycosis

Histoplasmosis

Coccidiomycosis

Paracoccidiomycosis

Cryptococcosis

Sporotrichosis

Aspergillosis

Chromoblastomycosis



 

Challenges for Neurosurgical Trainees

Neurosurgery is a new subspeciality of surgery with a very little progress in terms of clinical outcome despite of lot of technological advancements in last few decades. Neurosurgical management  has greatly been helped by advancements in neuroradiology like CT scan, MRI, and angiography. Very little progress has been witnessed over the innovative surgical skills and clinical outcome as reported during the period of Victor Horsley, Harvey Cushing and Walter Dandy about a century ago. As a trainee there is a need to have a bird eye view of the whole gamut of neurosurgery including Gamma knife, functional neurosurgery, neuro intervention, apart from learning skills of skull base neurosurgery, vascular neurosurgery , spinal instrumentation, repair of nerve injuries, surgery for craniosynostosis, spinal dysraphism, encephaloceles and neuroendoscopy. Some neurosurgical centers  may not have expertise and facilities for providing comprehensive teaching and training in neurosurgery.  

Cerebellar Astrocytoma

The common lesions of posterior fossa are: Brain Metastasis , Granulomas, Abscess, Glioma, Medulloblastoma, Hemangioblastoma, Meningioma, Arachnoid cyst, Acoustic Schwannoma, Epidermoid, etc.

Cerebellar Astrocytoma is the commonest primary intra-parenchymal tumor of the cerebellum in all age groups.

Common clinical presentation of cerebellar astrocytoma : 

Initially patient may present with headache, vomiting , instability while walking and gait disturbance ( postural instability) and on examination patient may have papilledema and positive cerebellar signs. At a later stage patient may become unconscious due to the tonsillar herniation and on examination patient may have bradycardia, hypertension and respiratory irregulaties ( Cushing Reflex due to raised intra-cranial pressure).

Management: The tumor of the cerebellum shoud be treated on urgent basis because of the risk of ventricular compression  ( obstruction of the fourth ventricle ) , compression of the brain stem, acute hydrocephalus and  tonsillar herniation.

Investigation

MRI brain with contrast with MR spectroscopy is the investigation of choice. It will depict:

1        Location of the lesion, whether it is intra-axial or extra-axial. Glioma is an intraaxial lesion because there will the brain parenchyma all around the lesion. On the contrary, Meningioma is an extra-axial lesion, which arises from the arachnoidal cap cells and grossly it appears  adherent to the dura, with broad dural base attachment and there is no brain parenchyma  on one side of the tumor.

2      Contrast image may show enhancement  of a part of the dura close to the tumor base, it is known as dural tail sign.

        3  Cerebellar astrocytoma is an intra-axial lesion and this tumor arises from the cerebellar parenchyma and is usually situated inside the cerebellar lobes. T1,T2, FLAIR, DWI sequences should be examined in conjunction with contrast image and MR spectroscopy. It may appear iso to hypointense on T1 weighted image and iso to hyperintense on T2 weighted image . The FLAIR ( Flow Attenuation Inversion Recovery) image may depict perilesional edema.

4    Contrast image can differentiate the astrocytoma from abscess ( hypointense on 1 weighted image, hyperintense on T2 weighted image, thick abscess wall which enhances on on contrast administration, MR spectroscopy may suggest infective pathology ), meningioma ( omogenous contrast enhancement, broad dural attachment, associated perilesional edema, dural tail sign, bony chages), Epidermoid, hemangioblastoma (cystic lesion with contrast enhancing mural nodule ) and other common lesions of the posterior fossa.

   5.  Asociatied brain stem compression , ventriculomegaly  or tonsillar herniation may be seen.

   6. MRI will give an idea about the consistency of the lesion, vascularity of the lesion and will be the most important tool for the preoperative surgical planning.
   Treatment:

If patient presents in an unconscious state and CT scan reveals a posterior fossa lesion with hydrocephalus then without wasting time, ventricular tap shoud be done to save life of the patient.

If patient presents in routine out- patient department setting , then neurosurgeon has some time to investigate the patient, however, at the outset antiedema measures should be started. Acetazolamide (Diamox 250 mg Thrice a day in an adult patient), Steroid ( Dexamethasone 4 mg four times a day in an adult patient ) should be initiated.

Suboccipital Craniectomy and tumor decompression should be done and depending upon the grade of the tumor patient should be given chemoradiation therapy.

Tumors of Central Nervous System ( Neuro-oncology)

               TUMORS  OF  CENTRAL  NERVOUS  SYSTEM

                                           Dr. VKS Gautam

It is very important to use authentic terms for the cns tumors and have an overall view about all the tumors of the central nervous system. Various nomenclatures and classifications are used for description. Therefore, it is imperative to know what is most authentic and easiest way to remember. The pathological classification of cns tumors is the most common and most practical way of nomenclature and classification of such tumors.

CNS tumors, especially gliomas, contrary to the other cancers of the body , cannot be classified like Benign or Malignant or  Cancer and Non cancer or like Benign lesion of the Breast ( Fibroadenoma) and Cancer of the breast ( Ca Breast) , or Benign Prostrate Hyperplasia (BPH) and Cancer of the Prostrate. On the contrary, the Gliomas or Astrocytomas are classified on the basis of features of neoplasia- like cellular atypia, nuclear proliferation, vascular proliferation & necrosis. So, there is a grading of neoplasia. Cushing and Bailey classification was an earlier effort to classify brain tumors.  World Health Organization ( WHO) classification of  tumors of central nervous system is a comprehensive,  authentic and up to date source of reference. I have made an effort to create an outline and curtail the details so that any doctor can have an overview of all the tumors of CNS. The details of all such tumors should  be read in conjunction with the radiological findings which is more interesting and easy.

About a century back Harvey Cushing published his work on brain tumors.
World Health Organization Classification of the Central Nervous System , fourth edition (WHO 2007), lists more than 120 types of brain tumors. This is broadly a histopathological classification.

How to understand about brain tumors?  We are very much familier with the nomenclature used in the older classifications . A comprehensive WHO classification of CNS tumors helps in understanding the characterstics of the brain tumors . So, while describing these tumors, for a better understanding,  older terms in conjuction with newer terms should be used.

GLIOMA is the commonest primary brain tumor. Glioma arises from glial cells. Since glial cells are far more in number than neuronal cells, it will be easy to understand the fact that gliomas are more common. Glial cells comprise of astrocytes, oligodendrocytes, ependymal cells so the gliomas can further be subclassified as astrocytoma ( commonest type of glioma ), oligodendroglioma and ependymoma.  According to WHO classification, these tumors can further be subclassified on the basis of features of malignancy ( microvascular proliferation, cellular atypia, mitotic activity , necrosis ) from grade I, II, III and IV.

AS neuronal cells are less in number than glial cells it is easy to remember that tumors like NEURONAL  & MIXED NEURONAL GLIAL TUMORS are less common , and relatively benign tumors . Gangliocytoma ( WHO grade I ) and ganglioglioma ( WHO grade I or III ) are well differentiated tumors composed of neoplastc mature appearing neurons alone ( gangliocytoma) or neoplastic ganglion cells combined with glioma cells ( ganglioglioma).  Dysplastc gangliocytoma of the cerebellum ( Lhermitte-Duclos disease, WHO grade I ) is associated with Cowden syndrome in 50 % cases.  Central Neurocytoma & extraventricular neurocytoma ( WHO grade II ) are low grade neoplasms of young adults.  Paraganglioma of the filum terminale ( WHO grade I ), Papillary glioneuronal tumor ( WHO grade I ) are surgically curable tumors.  Dysembryoplastic neuroepithelial tumors ( DNT; WHO grade I ) is a low grade quasihamartomatous tumor that occurs in childrenand young patients with history of long standing resistant seizures.

Summary of the WHO Classification of CNS Tumors ( 2007) for comprehensive but easy to recapitulate the overview of CNS tumors

1. Tumours of neuroepithelial tissue

1.1. Astrocytic tumours

        

        Pilocytic astrocytoma  & Subependymal giant cell astrocytoma (WHO grade I)

       

        Pilomyxoid astrocytoma & Pleomorphic xanthoastrocytoma (WHO grade II)

        

         Diffuse astrocytoma (WHO grade II) 

                        Variants:  protoplasmic,   gemistocytic,   fibrillary,  mixed

       

         Anaplastic astrocytoma (WHO grade III)

        

         Glioblastoma (WHO grade IV)

                                         a. Giant cell glioblastoma

                                         b. Gliosarcoma

    

          Gliomatosis cerebri (WHO grade III)

1.2. Oligodendroglial tumours

                 Oligodendroglioma (WHO grade II)

                 Anaplastic oligodendroglioma (WHO grade III)

1.3. Oligoastrocytic tumours

                 Oligoastrocytoma (WHO grade II)

                 Anaplastic oligoastrocytoma (WHO grade III)

1.4. Ependymal tumours

                 Subependymoma &  Myxopapillary ependymoma (WHO grade I)

                 Ependymoma (WHO grade II)

                 Anaplastic ependymoma (WHO grade III)

1.5. Choroid plexus tumours

                     Choroid plexus papilloma (WHO grade I)

                     Atypical choroid plexus papilloma ( WHO grade II)

                     Choroid plexus carcinoma (WHO grade III)

1.6. Other neuroepithelial tumours

                   Astroblastoma (WHO grade I)

                  Chordoid glioma of the third ventricle (WHO grade II)

                  Angiocentric glioma (WHO grade I)

1.7. Neuronal and mixed neuronal-glial tumours

                    Dysplastic gangliocytoma of cerebellum (Lhermitte-Duclos),

                    Desmoplastic infantile astrocytoma/ganglioglioma,

                    Dysembryoplastic neuroepithelial tumour, 

                    Gangliocytoma ,

                    Ganglioglioma

                    Papillary glioneuronal tumour

                    Rosette-forming glioneuronal tumour of the fourth ventricle, & 

                    Paraganglioma are WHO grade I tumors.

                    Central neurocytoma & Extraventricular neurocytoma , Cerebellar liponeurocytoma   (WHO grade II)

                    Anaplastic ganglioglioma (WHO grade III)

                                 

1.8. Tumours of the pineal region

               Pineocytoma (WHO grade I)

               Pineal parenchymal tumour of intermediate differentiation (WHO grade II, III)

               Pineoblastoma (WHO grade IV)

               Papillary tumors of the pineal region (WHO grade II, III)

1.9. Embryonal tumours

              Medulloblastoma (WHO grade IV)

              Medulloblastoma with extensive nodularity (WHO grade IV)

              Anaplastic medulloblastoma (WHO grade IV)

              CNS Primitive neuroectodermal tumour (WHO grade IV)

              CNS Neuroblastoma (WHO grade IV)

              Atypical teratoid/rhabdoid tumour (WHO grade IV)

2. Tumours of cranial and paraspinal nerves

              Schwannoma (WHO grade I)

              Neurofibroma (WHO grade I)

              Perineurioma (WHO grade I, II, III)

              Malignant peripheral nerve sheath tumour (MPNST) (WHO grade II, III, IV)

3. Tumours of the meninges

3.1 Tumours of meningothelial cells

 Meningioma

                   Variants ( Subtypes ): meningothelial,  fibrous (fibroblastic),  transitional (mixed),  psammomatous,  angiomatous,  microcystic,  secretory,  clear cell,  chordoid,  lymphoplasmacyte-rich, and  metaplastic

 

 Atypical meningioma (WHO grade II)

 Anaplastic meningioma (WHO grade III)

3.2 Mesenchymal tumours

 Lipoma , Angiolipoma ,Liposarcoma,  Leiomyoma,  Leiomyosarcoma, Solitary fibrous tumour ,  Fibrosarcoma , Rhabdomyoma, Rhabdomyosarcoma,Chondroma , Chondrosarcoma,  Osteoma,Osteosarcoma, Osteochondroma, Angiosarcoma, Kaposi Sarcoma, Ewing Sarcoma - PNET 

 Malignant fibrous histiocytoma

 Hibernoma

 Haemangioma 

 Epithelioid hemangioendothelioma

 Haemangiopericytoma & Anaplastic haemangiopericytoma (WHO grade III)

3.3 Primary melanocytic lesions

                      Diffuse melanocytosis

                      Melanocytoma 

                      Malignant melanoma 

                      Meningeal melanomatosis 

3.4 Other neoplasms related to the meninges

                     Haemangioblastoma (WHO grade I)

4. Tumors of the haematopoietic system

                       Malignant Lymphomas

                        Plasmocytoma

                        Granulocytic sarcoma

5. Germ cell tumours

                             Germinoma

                             Embryonal carcinoma

                             Yolk sac tumour

                             Choriocarcinoma

                             Teratoma

                             Mixed germ cell tumours

6. Tumours of the sellar region

                                Craniopharyngioma (WHO grade I)

                                Granular cell tumour (WHO grade I)

                                Pituicytoma (WHO grade I)

                                Spindle cell oncocytoma of the adenohypophysis (WHO grade I)

7. Metastatic Tumours


The 2016 WHO Classification of CNS Tumors
The most recent and updated classification of CNS tumors is published by WHO in year 2016.
The new classification uses both molecular parameters and histological features, so, it is a combined genotype and phenotype classification. Previous classifications were mainly based on the microscopic histological features, immunohistochemical expressions and putative cell of origin of the tumors.
Over the past few decades there had been a better understanding of the genetic basis of tumorigenesis. The use of integrated phenotypic and genotypic parameters for the  CNS tumor classification  adds a level of objectivity in the diagnostic process leading to greater diagnostic accuracy as well as improved patient management and more accurate determination s of prognosis and treatment response.
So, the new classification proposed by WHO incorporates genetically defined entities and restructured the entire classification of tumors of central nervous system  into the molecular era. Certain terms had been added and some old terms had been deleted into the new classification.
The nosological shift to a new classification based on both phenotype and genotype.

The most recent and updated classification of CNS tumors is 2016-WHO classification.

WHO (2016) Classification of Tumors of Central Nervous System

In year 2016, for the first time, the World Health Organization ( WHO) classification of CNS tumors uses molecular parameters in addition to histology to define many tumor entities. Major restructuring has been done in diffuse gliomas, medulloblastomas and other embryonal tumors. It has added newly recognized neoplasms, and has deleted some entities, variants and patterns that are no longer have diagnostic and/or biological relevance.

Summary of changes in new classification

• Major restructuring of diffuse gliomas, Medulloblastomas, other embryonal tumors & incorporation of genetically defined entities
• The term “primitive neuroectodermal tumor” is removed
• Incorporation of a genetically defined ependymoma variant - RELA fusion positive
• 
  
  Addition of
            Newly recognized entities, variants and patterns have been added:
                            1.  IDH-wildtype and IDH-mutant glioblastoma 
                            2. Diffuse midline glioma, H3 K27M–mutant
                            3. Embryonal tumour with multilayered rosettes, C19MC-altered
                            4. Ependymoma, RELA fusion–positive
                            5. Diffuse leptomeningeal glioneuronal tumor
                            6. Anaplastic PXA
                            7. Epithelioid glioblastoma  
                             8. Glioblastoma with primitive neuronal component
                             9. Multinodular and vacuolated pattern of ganglion cell tumor
  Deletion of
              Gliomatosis cerebri
              Protoplasmic and fibrillary astrocytoma variants
              cellular ependymoma variant
              Primitive Neuroectodermal tumor
  
  

• Addition of Brain invasion as a criterion for atypical meningioma
• Restructuring of solitary fibrous tumor and hemangiopericytoma ( SFT/HPC) as one entity
• Expansion & clarification of entities included in of Nerve sheath tumors, with addition of hybrid nerve sheath tumors & separation of melanotic schwannoma from other schwanomas
• Expansion of entities included in hematopoietic/lymphoid tumors of the CNS ( lymphomas & histiocytic tumors)
                       
                                     NEW CLASSIFICATION
  Diffuse astrocyic and oligodendroglial tumors

• Diffuse astrocytoma, IDH-mutant
                          Gemistocytic astrocytoma, IDH-mutant

•  Diffuse astrocytoma, IDH-wildtype
•  Diffuse astrocytoma, NOS
• Anaplastic astrocytoma, IDH-mutant
• Anaplasticastrocytoma, IDH-wildtype
• Anaplastic astrocytoma, NOS

• Glioblastoma, IDH-wildtype
                       Giant cell glioblastoma
                       Gliosarcoma
                       Epitheloid glioblastoma

• Glioblastoma, IDH-mutant
• Glioblastoma, NOS

• Diffuse midline glioma, H3 K27M-mutant
• Oligodendroglioma, IDH-mutant and 1p/19q-codeleted
• Oligodendroglioma, NOS
  
  

• Anaplastic Oligodendroglioma, IDH-mutant and 1p/19q-codeleted
• Anaplastic oligodendroglioma, NOS
  
  

• Oligoastrocytoma, NOS
• Anaplastic Oligoastrocytoma, NOS
  Other astrocytic tumor

• Pilocytic astrocytoma
                   Pilomyxoid astrocytoma

• Subependymal giant cell astrocytoma
• Pleomorphic xanthoastrocytoma
• Anaplastic pleomorphic xanthastrocytoma
  Ependymal tumors

• Subependymoma
• Myxopapillary ependymoma
• Ependymoma
                  Papillary ependymoma
                  Clear cell ependymoma
                  Tanycytic ependymoma

• Ependymoma, RELA fusion-positive
  Anaplastic ependymoma
  Other gliomas

• Choroid glioma of the third ventricle
• Angiocentric glioma
• Astroblastoma
  Choroid plexus tumors

• Choroid plexus papilloma
• Atypical choroid plexus papilloma
• Choroid plexus carcinoma
  Neuronal & mixed Neuronal-glial tumors

• Dysembryoplastic neuroepithelial tumor
• Gangliocytoma
• Ganglioglioma
• Anaplastic ganglioglioma
• Dysplastic cerebellar gangliocytoma ( Lhermitte-Duclos disease)
• Desmoplastic infantile astrocytoma and ganglioglioma
• Papillary glioneuronal tumor
• Rosette forming glioneuronal tumor
• Diffuse leptomeningeal glioneuronal tumor
• Central neurocytoma
• Extraventricular neurocytoma
• Cerebellar liponeurocytoma
• Paraganglioma
  Tumor of the Pineal region

• Pineocytoma
• Pineal parenchymal tumor of intermediate differentiation
• Pineoblastoma
• Papillary tumor of pineal region
  Embryonal tumors
  Medulloblastoma, genetically defined
                         Medulloblastoma, WNT activated
                         Medulloblastoma, SHH-activated and T53-mutant
                         Medulloblastoma, SHH-activated and T53-wildtype
                         Medulloblastoma,  non-WNT/non SHH
                                  Medulloblastoma,  group 3
                                  Medulloblastoma, group 4
  Medulloblastoma, histologically defined
                         Medulloblastoma, classic
                         Medulloblastoma, desmoplastic/nodular
                         Medulloblastoma with extensive nodularity
                         Medulloblastoma, large cell/anaplastic
  Medulloblastoma NOS

• Embryonal tumor with multilayered rosettes, C19MC-altered
• Embryonal tumor with multilayered rosettes, NOS
• Medulloepithelioma
• CNS Neuroblastoma
• CNS ganglioneuroblastoma
• CNS embryonal tumor, NOS
• Atypical teratoid/ rhabdoid tumor
• CNS embryonal tumor with rhabdoid features
  
  
  Tumors of cranial and paraspinal nerves
  Schwannoma
            Cellular Schwannoma
            Plexiform Schwannoma
            Melanotic Schwannoma
  Neurfibroma
            Atypical neurofibroma
            Plexiform neurofibroma
  Perineurioma
  Hybrid nerve sheath tumors
  Malignat peripheral nerve sheath tumor
              Epitheloid MPNST
              MPNST with perineurial differentiation
  
  
  Meningioma

• Meningioma
• Meningothelial meningioma
• Fibrous meningioma
• Transitional meningioma
• Psammomatous meningioma
• Angiomatous meningioma
• Microcystic meningioma
• Secretory meningioma
• Lymphoplasmacyte-rich meningioma
• Metaplastic meningioma
• Chordoid meningioma
• Clear cell meningioma
• Atypical meningioma
• Papillary meningioma
• Rhabdoid meningioma
• Anaplastic ( malignant) meningioma 
  
  
  Mesenchymal, Non-meningothelial tumors

• Solitary fibrous tumor/hemangiopericytoma
• Hemangioblastoma
• Hemangioma
• Epitheloid hemangioendothelioma
• Angiosarcoma,
• Kaposi Sarcoma,
• Ewing sarcoma/ PNET
• Lipoma
• Angiolipoma
• Hibernoma
• Liposarcoma
• Desmoid type fibromatosis
• Myofibriblastoma

•  Inflammatory myofibroblastic tumor
• Benign fibrous histiocytoma
• Leiomyoma
• Leiomyosarcoma
• Rhabdomyoma
• Rhabdomyosarcoma
• Chondroma’
• Chondrosarcoma
• Osteoma
• Osteochondroam
• Osteosarcoma
  Melanocytic tumors

• Meningeal melaonocytosis
• Meningeal melanocytoma
• Meningeal melanoma
• Meningeal melanomatosis
  Lymphoma

• Diffuse large B-cell lymphoma of the CNS 
• Immunodeficiency-associated CNS lymphoma
                            AIDS-related diffuse large B-cell lymphoma
                            EBV-positive diffuse large B-cell lymphoma, NOS
                            Lymphomatoid granulomatosis 

• Intravascular large B-cell lymphoma 
• Low-grade B-cell lymphoma of the CNS 
• T-cell & NK/T cell-lymphoma of the CNS 
• Anaplastic large cell lymphoma , ALK-positive 
• Anaplastic large cell lymphoma , ALK-negative 
• MALT lymphoma of the dura
  Histiocytic tumors

• Langerhans cell histocytosis
• Erdheim-Chester disease
• Rosai-Dorfman disease
• Juvenile xanthogranuloma
• Histiocytic sarcoma
  Germ cell tumors

• Germinoma
• Embryonal carcinoma
• Yolk sac tumor
• Choriocarcinoma
• Teratoma
                   Mature, Immature

• Teratoma with malignant transformation
• Mixed germ cell tumor
  Tumors of the sellar region
  Craniopharyngioma
               Admantinomatous craniopharyngioma
               Papillary craniopharyngioma
  Granular cell tumor of sellar region
  Pituicytoma
  Spindle cell oncocytoma
  Metastatic tumors
  
  
  
  
  
  
  
  
  
  
          
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

Sources
Review article
The World Health Organization  classification of tumors of the central nervous system: a summary. David N. Louis, et al. Acta Neuropathol ( 2016) 131:803-820