Grading of the tumors of the central nervous system
Encyclopedia
The concept of grading of the tumors of the central nervous system, agreeing for such the regulation of the "progressiveness" of these neoplasias (from benign and localized tumors to malignant and infiltrating tumors), dates back to 1926 and was introduced by P. Bailey and H. Cushing,
in the elaboration of what turned out the first systematic classification of gliomas.
In the following, the grading systems present in the current literature are introduced. Then, thru a table, the more relevant are compared.
) dates 1994.
In 1976 the World Health Organization
(WHO) publishes the first edition of the International Classification of Diseases for Oncology
(ICD-O), now at the third edition (ICD-O-3, 2000).
In this last edition, the Arabic numeral after the character "/" indicates the "behavior" of the neoplasia, with the following meaning:
For the concepts of benign and malignant neoplasia see Tumor
and Cancer
.
For primary and secondary neoplasias see Metastasis
.
A brain tumor composed of benign cells, but located in a vital area (as the brain is), can be considered to be life-threatening — although the tumor and its cells would not be classified as malignant.
defines progressive malignancy of astrocytomas as follows:
also is used to grade astrocytomas; however, this system uses four morphologic criteria to assign a grade:
a) nuclear atypia
,
b) mitosis
,
c) endothelial proliferation
-'piled-up' endothelial cells. NOT hypervascularity
d) necrosis
.
The St. Anne-Mayo grade has four categories of tumors:
Data collection of primary central nervous system tumors. National Program of Cancer Registries Training Materials.
Atlanta, Georgia: Department of Health and Human Services, Centers for Disease Control and Prevention.
is contained in the volume Histological Typing of Tumours of the Central Nervous System, whose first edition dates back to 1979, the second to 1993 and last one to 2007.
The WHO grade has four categories of tumors:
From the histological point of view the WHO system is based on the same criteria as the St Anne-Mayo system.
Central nervous system tumors.
Mayo Clin Proc. 2007 Oct;82(10):1271-86.
{|class="wikitable" border="1" style="text-align:center"
{| border=1
! Nome WHO!! WHO grade!! Kernohan grade!! St Anne/Mayo grade!! St Anne/Mayo criteria
|-
| Pilocytic astrocytoma|| I|| -|| 1|| 0 criterion
|-
| Diffuse astrocytoma|| II|| 1|| 2|| 1 criterion (a)
|-
| Anaplastic astrocytoma|| III|| 2|| 3|| 2 criteria (a+b)
|-
| Glioblastoma|| IV|| 3/4|| 4|| 3-4 criteria (a+b[+/-c]+d)
|}
in the elaboration of what turned out the first systematic classification of gliomas.
In the following, the grading systems present in the current literature are introduced. Then, thru a table, the more relevant are compared.
ICD-O scale
The first edition of the International Classification of Diseases (ICD) dates back to 1893, the current review (ICD-10ICD-10
The International Statistical Classification of Diseases and Related Health Problems, 10th Revision is a medical classification list for the coding of diseases, signs and symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases, as maintained by the...
) dates 1994.
In 1976 the World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
(WHO) publishes the first edition of the International Classification of Diseases for Oncology
International Classification of Diseases for Oncology
The International Classification of Diseases for Oncology is a domain specific extension of the International Statistical Classification of Diseases and Related Health Problems for tumor diseases. This classification is widely used by cancer registries.It is currently in its third revision ....
(ICD-O), now at the third edition (ICD-O-3, 2000).
In this last edition, the Arabic numeral after the character "/" indicates the "behavior" of the neoplasia, with the following meaning:
- /0 benign neoplasia
- /1 uncertain neoplasia (benign or malignant)
- /2 neoplasia in situIn situIn situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...
- /3 primary infiltrative malignant neoplasia
- /6 secondary malignant neoplasia
- /9 malignant neoplasia, uncertain if primitive or secondary
For the concepts of benign and malignant neoplasia see Tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
and Cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
For primary and secondary neoplasias see Metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
.
A brain tumor composed of benign cells, but located in a vital area (as the brain is), can be considered to be life-threatening — although the tumor and its cells would not be classified as malignant.
Kernohan grading
The Kernohan grading systemdefines progressive malignancy of astrocytomas as follows:
- Grade 1 tumors are benign astrocytomas.
- Grade 2 tumors are low-grade astrocytomas.
- Grade 3 tumors are anaplastic astrocytomas.
- Grade 4 tumors are glioblastomas.
St Anne-Mayo grading
The St Anne-Mayo grading systemalso is used to grade astrocytomas; however, this system uses four morphologic criteria to assign a grade:
a) nuclear atypia
Atypia
Atypia is a clinical term for abnormality in a cell. The term is medical jargon for an atypical cell. Atypia: Etymology: Gk, a + typos, without type; a condition of being irregular or nonstandard....
,
b) mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
,
c) endothelial proliferation
Cell growth
The term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...
-'piled-up' endothelial cells. NOT hypervascularity
d) necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
.
The St. Anne-Mayo grade has four categories of tumors:
- Grade 1 tumors do not meet any of the criteria.
- Grade 2 tumors meet one criterion, usually nuclear atypia.
- Grade 3 tumors meet two criteria, usually nuclear atypia and mitosis.
- Grade 4 tumors meet three or four of the criteria.
WHO grading
The World Health Organization (WHO) grading systemData collection of primary central nervous system tumors. National Program of Cancer Registries Training Materials.
Atlanta, Georgia: Department of Health and Human Services, Centers for Disease Control and Prevention.
is contained in the volume Histological Typing of Tumours of the Central Nervous System, whose first edition dates back to 1979, the second to 1993 and last one to 2007.
The WHO grade has four categories of tumors:
- Grade I tumors are slow-growing, nonmalignant, and associated with long-term survival.
- Grade II tumors are relatively slow-growing but sometimes recur as higher grade tumors. They can be nonmalignant or malignant.
- Grade III tumors are malignant and often recur as higher grade tumors.
- Grade IV tumors reproduce rapidly and are very aggressive malignant tumors.
From the histological point of view the WHO system is based on the same criteria as the St Anne-Mayo system.
Central nervous system tumors.
Mayo Clin Proc. 2007 Oct;82(10):1271-86.
Comparison of the grading systems
In the following table the various grading systems are compared (the IDC-O scale is not comprised because it is not considered a real grading system):{|class="wikitable" border="1" style="text-align:center"
{| border=1
! Nome WHO!! WHO grade!! Kernohan grade!! St Anne/Mayo grade!! St Anne/Mayo criteria
|-
| Pilocytic astrocytoma|| I|| -|| 1|| 0 criterion
|-
| Diffuse astrocytoma|| II|| 1|| 2|| 1 criterion (a)
|-
| Anaplastic astrocytoma|| III|| 2|| 3|| 2 criteria (a+b)
|-
| Glioblastoma|| IV|| 3/4|| 4|| 3-4 criteria (a+b[+/-c]+d)
|}
External links
- AFIP Course Syllabus - Astrocytoma WHO Grading Lecture Handout