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Detection of clinically relevant abnormalities in genes There are two broadly related areas of clinical practice that rely on molecular analysis. First, analysis of tumour DNA may improve diagnostic precision, enhance treatment plans and help predict clinica...

Electron microscopy Electron microscopy allows visualisation of tissue at very high magnification, e.g. × 1000 to × 500 /uni00A0 000. It may help to decide the lineage of a non-neoplastic or neoplastic cell and may help to determine the nature of abnormal depo...

FURTHER READING Brierley JD, Gospodarowicz MK, Wittekind C. TNM classification of malignant tumours , 8th edn. Oxford: Wiley-Blackwell, 2017. Cardesa A, Zidar N, Alos L et al . The Kaiser’s cancer revisited: was Virchow totally wrong? Virchows Arch 2011; 458(6)...

FURTHER WORK Pathologists request further stains or other tests on a signif - icant minority of histology specimens. This includes special stains, immunohistochemistry , in situ hybridisation and various molecular pathology techniques. Electron microscopy may...

Flow cytometry Flow cytometry is a laser-based or impedance-based technique used for cell counting, cell sorting, biomarker detection and protein engineering. Cells are suspended in a stream of fluid and passed by an electronic detection apparatus. It is usefu...

Fresh tissue The most common indication for submission of a fresh tissue sample (i.e. without the usual formalin or any other fixative) is rapid frozen section diagnosis, usually done intraoperatively . Other indications are microbiological assessment, electro...

Genomic changes in tumours In normal circumstances, there is precise control of the divi - sion and proliferation of human cells. For example, various growth factors influence division by binding to specific cell surface tyrosine kinase receptors, resulting in...

HER2 gene amplification HER2 status influences the selection of therapy for breast cancer and metastatic gastric adenocarcinoma. Tumours with HER2 amplification may be treated with the monoclonal antibodies trastuzumab or pertuzumab, often in combination with ot...

Histological assessment In a histological preparation, the microscopic structure of the tissue remains intact, allowing direct visualisation of tissue architecture. Accordingly , the pathologist can see not only the characteristics of the cells that form the...

Histological types of malignancy A malignant tumour showing features of epithelial di ff erentia - tion, and typically arising in an epithelial layer, is a carcinoma. Other important types of malignancy include malignant mela - noma (melanocytes) ( Figure 11....

Histology specimen On arrival in the pathology laboratory , specimens receive a unique identification number, usually with a barcode. They proceed to macroscopic assessment and sampling (colloquially - known as ‘cut up’). The largest specimens require initial o...

Histology Specimens for histology are classified as biopsies and resec - tions, although strictly speaking all samples are biopsies. The reasons for taking small biopsies include diagnosis, further assessment and prognostic prediction. Types of small biopsy in...

Immunohistochemistry: tumour pathology Immunohistochemistry has multiple applications in tumour pathology , including elucidation of site of origin and determi nation of cell type/direction of di ff erentiation. Immunohisto chemistry may also help to confirm...

Immunohistochemistry Immunohistochemistry emerged in the 1970s and has had a major impact on histopathological diagnosis. The technique detects a specific antigen using an antibody . The antibody is ). labelled with a dye and after binding to its target antigen...

INTRODUCTION Pre-nineteenth century tissue diagnosis depended on naked eye examination of autopsy material and of a small selection of surgical specimens. The development of the light micro scope allowed closer examination of tissue from autopsies and surgi...

Learning objectives To understand: The value and limitations of tissue diagnosis • Approaches to tissue processing • Learning objectives To understand: The value and limitations of tissue diagnosis • Approaches to tissue processing • Learning objectives To und...

Microscopic features of inflammation Acute inflammation is characterised histologically by neutro - phils (polymorphonuclear leukocytes), erosion or ulceration ( Figure 11.18 ) and chronic inflammation by lymphocytes and plasma cells. Other inflammatory cells incl...

Mismatch repair gene abnormalities in tumours High levels of microsatellite instability (MSI-H), also known as deficient mismatch repair (D-MMR), occur as a result of germ line mutations or acquired somatic events in the MMR genes ( MLH1, MSH2, MSH6 and PMS2 ...