Understanding Metastasis

Metastasis in Greek means displacement.

The term is used to denote the spread of a disease from one organ or part to another non-adjacent organ or part.

Malignant tumor cells and infections have the established capacity to metastasize. Until specified otherwise the term metastasis usually denotes malignant spread.

Why Does Metastasis occur?

Cancer cells can break away, leak, or spill from a primary tumor, enter lymphatic and blood vessels, circulate through the bloodstream, and be deposited within normal tissue elsewhere in the body.

Metastasis is one of three hallmarks of malignant tumors.

Different tumors have different capacity to metastasize.

When tumor cells metastasize, the new tumor is called a secondary or metastatic tumor. This is done to differentiate it from original source or primary tumor.

However, the cells of  new secondary tumor are similar to the primary tumor [Read more...]

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A Brief Note About Markers Used In Tumors

finalmusculoskeletaltumor-copy.jpgThis is abrief article about various substances that are expressed in the body and are used as tumour markers too.

Epithelial Markers

Keratins are the markers most frequently used in the identification of epithelial phenotypes.

Epithelial membrane antigen (EMA)

EMA represents a membrane glucoprotein that is most likely similar or identifical to the casein fraction of human milk. It is expressed by virtually all epithelial cells and neoplasm of epithelial origin. It is also expressed on a wide range of tumors of mesenchymal origin and even on some lymphomas. [Read more...]

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A Brief Note On Intermediate Filaments and There Use In Skeletal Tumours

cat_musculoskeletal_pathology.jpgIntermediate filaments are ubiquitous cytoplasmic structures that are about 10 nm thick. They have a uniform appearance and represent a nonbranching, fine filamentous, cytoplasmic material.

On the basis of their chemical compositionthey can be separated into five major groups: vimentin, keratins, desmin, glial fibrillary acidic protein, and neurofilaments.

[Read more...]

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Use of Immunohistochemistry

cat_musculoskeletal_pathology.jpgImmunohistochemistry has become a generally accepted and widely used auxiliary method of diagnostic pathology, including the pathology of bone tumors and tumor like lesions.

This method has emerged as a diagnostically useful technique because of the development of highly specific antibodies and the invention of sensitive immune and enzymatic detection systems. The fluorescence detection methods are more often used in investigative studies and are rarely sued in diagnostic pathology. [Read more...]

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Use of Histomorphometry

cat_musculoskeletal_pathology.jpgHistomorphometry represents a microscopic planimetry or stereology. It is used to study homeostasis of the skeleton, mainly in metabolic disorders of bone. The technique is occasionally used to evaluate the skeletal status and treatment effect of rickets and osteomalacia associated with tumors.

For histomorphometry, undecalcified bone sections stained with techniques that enable the visualization of calcified and uncalcified osteoid such as von Kossa’s or Goldner’s (modified trichrome) stains are used. Another frequently used technique is tetracycline-pulse labeling for epifluorescence. [Read more...]

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Cytophotometry or Image Analysis

cat_musculoskeletal_pathology.jpgCytophotometry, or image analysis, is conceptually similar to flow cytometery but requires a different preparations of cells for the measurements. The principle of this technique is the measurement of the optical density of cells in histological section or, even better, of whole cells spread in histological section or, even better, of whole cells spread on the glass. [Read more...]

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Flow Cytometery

cat_musculoskeletal_pathology.jpgFlow cytometers are machines constructed to measure and record flurescence on particles or cells stained with fluorochrome and flowing in suspension past an excitation source, typically a laser beam.

The fluorescence levels of the individual cells are captured by a photomultiplier tube, converted into an electric pulse, and stored and analyzed by a computer.

The cells can also be stained with multiple fluorochromes and can be excited by two different laser beams. This technique known as multiparameter flow cytometry, helps analyze several cellular components and their relationships.

Some other cellular features, such as light scattering at small angles, pulse width, or electrical conductivity, related to some extent to cell seize, can also be measured. [Read more...]

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Use of Electron Microscopy

cat_musculoskeletal_pathology.jpg

Examination of ultrastructural features of cellular and extracellular structures is a powerful diagnostic tool. The introduction of the transmission electron microscope in the early decades of the twentieth century dramatically expanded the investigative and diagnostic capabilities to study the submicroscopic details of diseased tissue including bone tumors and tumor like condition.

Use of the transmission through a thin section of tissue impregnated with electrondense material and embedded in plastic material and embedded in plastic medium is the most applicable for diagnostic purposes. [Read more...]

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Special Stains-Amyloid, Hemosiderin, Melanin and Calcium Stains

Amyloid stain

Staining for amyloid is one of the most useful special techniques. The Congo red stain and examination with nonpolarized and polarized light are the most frequently used techniques. The dye binds the beta-pleated arrangement of amyloid and has no chemical specificity.

This is seen as a reddish deposit under nonpolarized light. Green birefringence is present when the sections are examined under polarized light. Excessive or prolonged exposure to Congo red can cause binding to the tissue that is unrelated to the presence of amyloid. [Read more...]

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Special Stains-Trichrome and Stains For Microorganisms

Trichrome Stain

The trichrome stain is frequently used to demonstrate the presence of extracellular substances such as collagen. It is sometimes used in research investigation of soft and skeletal tissue, but is has minimal diagnostic applicabilities. As the name implies, the technique uses three dyes that stain nuclei, cytoplasm, and extracellular matrix, primarily the collagen.

This technique is rarely used in the diagnosis of tumors, but is frequently used for histomorphometric evaluation of mineralized versus nonmineralized osteoid in metabolic bone disease. [Read more...]

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