Neoplasia - grading, staging and classification Flashcards
What is the difference between hyperplasia, dysplasia and neoplasia?
Other types of cell may increase in numbers in response to appropriate stimuli. For example, in a guitar player, the basal cells of the epidermis in the fingertips can proliferate to produce hard pads of keratin (calluses) caused by repeated contact with the strings. Cell proliferation and the consequent increase in cell numbers seen in these two examples is called hyperplasia. It is a normal physiological response to demand placed on a tissue. The numbers of each cell type are controlled specifically. For example, the numbers of erythrocytes in the blood is controlled by a hormone, erythropoietin; an increase in erythrocyte numbers does not produce any concomitant increase in leukocyte numbers, since leukocyte subsets are each subject to their own controls on cell number.
If cell division becomes poorly regulated, cells may lose some of their morphological characteristics and/or functions. The tissue becomes disordered in appearance, often with an increase in the numbers of immature cells, and greater variability between cells. This appearance is called dysplasia. It should be emphasised that dysplasia does not necessarily show that the cells have become cancerous; however, it does suggest underlying changes in the cells, which may predispose to cancer. In this sense dysplasia may be a stage on the way to cancer development. For example, when histologists screen cervical smears, they are particularly looking for changes in the normal morphology of the cells which indicate pre-cancerous changes.
Neoplasia is the term used to describe the development of tumours or cancerous tissue. The development of a tumour requires a series of changes in the biology of the cell, with progressive loss of the controls that limit cell division. Even a cell which is undergoing uncontrolled proliferation will not necessarily be malignant. Malignancy typically arises when the dividing cells invade the normal tissue and move away from their site of origin. Because of the great variety of different tumours, it is impossible to generalise. Nevertheless it is very important for a pathologist to be able to distinguish between a benign tumour and a malignant cancer, since the treatment required will usually be radically different. Consequently, pathologists often grade tumours according to how malignant/invasive they are. Histologists can get some impression of the rate of cell division within a tissue according to the number of mitotic figures - the number of cells with the nucleus showing the characteristic pattern of separating chromosomes, seen as the cell divides (Figure 9). Invasion of tumour cells within the tissue can be estimated by observing where the cells are in relation to their normal position and in relation to other cells in that tissue, and this forms an important element in the pathological report on a tumour.
What is the difference between histology and cytology?
Histology = the study of cells + tissue
Cytology = just the study of cells
What are the histological and cytological features of a malignant mass?
Tissue structure = disorganised arrangement of cells and invasion of the abnormal cells in surrounding tissue (poor tumour boundary)
Cell structure = large number of visibly dividing/mitotic cells, large variably shaped nuclei and large nucleus size (comapred to cytoplasm), variation in size and shape of the cell and loss of some normal cells features,
What is something you can prove of a collection of cells that makes it a good indicator of neoplasm? and what is an example of a cancer that cells show this property?
That the cells are monoclonal (they have all originated from the same parent cell).
Multiple myeloma. A neoplasm of the plasma cells that results in the production of a single antibody as all the cells are monoclonal.
How are tumours classified? Describe these two aspects.
They are graded and staged.
Grading -
a measure of the RATE of growth of the tumour based on histological examination
Staging - a measure of the EXTENT of tumour growth based on clinical, radiological and pathological features
Using breast cancer as an example, what features of cells do histologists look at under the microscope to determine the grade of a tumour? (what featured indicate how fast its proliferating)
- Differentiation - if its well differentiated (the cells look normal) it will grow slower whereas if it is poorly differentiated (abnormal looking cells and lacking normal tissure structure) these tumours will grow more rapidly. eg how much of the tissue has normal breast glands present
- Nuclear changes - an evaluation of size and shape of the nucleus in the tumour cells
- Mitotic activity - an ealuation of how many actively mitotic cells there are which is a direct indication of how fast the cells are dividing/growing.
Each of the categories gets a score between 1 and 3; a score of “1” means the cells and tumor tissue look the most like normal cells and tissue, and a score of “3” means the cells and tissue look the most abnormal. The scores for the three categories are then added, yielding a total score of 3 to 9. Three grades are possible:
Total score = 3–5: G1 (Low grade or well differentiated)
Total score = 6–7: G2 (Intermediate grade or moderately differentiated)
Total score = 8–9: G3 (High grade or poorly differentiated)
In general cancers, how are tumour graded? (eg grade 1, 2, 3 or 4)
Grading systems differ depending on the type of cancer. In general, tumors are graded as 1, 2, 3, or 4, depending on the amount of abnormality. In Grade 1 tumors, the tumor cells and the organization of the tumor tissue appear close to normal. These tumors tend to grow and spread slowly. In contrast, the cells and tissue of Grade 3 and Grade 4 tumors do not look like normal cells and tissue. Grade 3 and Grade 4 tumors tend to grow rapidly and spread faster than tumors with a lower grade.
If a grading system for a tumor type is not specified, the following system is generally used (1):
GX: Grade cannot be assessed (undetermined grade)
G1: Well differentiated (low grade)
G2: Moderately differentiated (intermediate grade)
G3: Poorly differentiated (high grade)
G4: Undifferentiated (high grade)
The TNM staging system is used to stage cancers, what is each of these letters measuring?
T = the size of the primary tumour N = the metastastic spread to lymph nodes M = the metastatic spread to other tissue/organs
Each is given an X (cant measure) a 0 (not present) or a 1,2,3 to rate the extent of each of these problems.
What is an indicator in a blood test that the cancer has spread to the bone?
Increased calcium in the blood as the calcium is released from bone breakdown.
What is the name given to cancer benign and malignant neoplasms of:
the surface epithelium and glandular epithelium?
melanocytic?
connective tissue? (whats the suffix)
Lymph nodes? (only malignant)
Bone marrow? (only malignant)
CNS? (only malignant)
Surface = papilloma to carcinoma Glandular = adenoma to adenocarcinoma
Melanocytic = naevi (moles) to melanoma
CT = “-sarcoma”
Lymph nodes = lymphoma
Bone marrow = leukaemia (blood produced here) or multiple myeloma
CNS = glioma
What process occurs to benign epithelial tumours that indicates they may be re-malignant?
Dysplasia
What commonly preceeds the diagnosis of a carcinoma as malignant? (remember carcinomas are cancer of the epithelium)
In situ growth phase - this is an early stage in cancer developement where the cancer cells/tumour is still onlyy confined to the epithelium.
Carcinomas are often identified as cohesive polygonal cells, what does this mean?
Cohesive = they cluster/stick together Polygonal = there are irregularly angular shaped cells with 4 or more sides (not rounded, they have straight sides)
What is a melanocytic naevi?
A mole. It is a benign cluster of pigment cells (melanocytes). These contain the pigment melanin to make they black or brown in colour.
What are some of the histological features of a melanoma?
Spindle cells, round cells or pleomorphic cells (a combination of different types and shapes and sizes of cells)
