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Molecular changes and drug therapy An increasingly common reason for molecular testing and related immunohistochemistry is the prediction of the response of advanced malignant tumours to specific drugs whose target is usually known (‘theranostics’). For examp...

Molecular profile: examples of specific tumours Colorectal carcinoma In CRC, the anti-EGFR monoclonal antibodies cetuximab and panitumumab are used in combination with chemotherapy for metastatic disease. These drugs are less likely to be e ff ective if KRAS or N...

Non-neoplastic and inflammatory conditions The diagnosis, assessment and management of non-neoplastic disease generates numerous pathology specimens. Examples include appendectomy for appendicitis, cholecystectomy for gallstone disease, hysterectomy for fibroid...

Other terms Other specific tissue abnormalities are also detectable by microscopy . Histopathologists may use specific terms. Some examples are as follows. /uni25CF Hyperplasia: an increase in cell number. /uni25CF Hypertrophy: an increase in cell size. /uni25CF...

PRINCIPLES OF MICROSCOPIC DIAGNOSIS Diagnosis of malignancy Neoplasia is a broad term that includes benign and malignant tumours and precursors of malignancy . The word ‘cancer’ is not precise, derives from observations of the similarities - between crabs and...

PRINCIPLES OF MICROSCOPIC DIAGNOSIS Diagnosis of malignancy Neoplasia is a broad term that includes benign and malignant tumours and precursors of malignancy . The word ‘cancer’ is not precise, derives from observations of the similarities - between crabs and...

Polymerase chain reaction The polymerase chain reaction (PCR) amplifies DNA, yield ing millions of copies from a single copy of a selected target. Amplification of RNA is also possible, using the technique of reverse transcriptase PCR (RT-PCR). It is worth n...

Prognosis Tests that help determine the selection of therapy for tumours may also have additional prognostic value. For example, a BRAF mutation in metastatic CRC is associated with a very - poor prognosis. Commercially available multiple molecular marker tes...

Prognostic factors for malignant tumours Tissue assessment is important for cancer prognosis. Stage is generally the most important prognostic factor for carcinomas. The internationally accepted Union for International Cancer Control (UICC)/American Joint Comm...

REASONS FOR ASSESSMENT OF TISSUE The contributions that tissue analysis makes to clinical - management include diagnosis, staging, prediction of outcome and assistance with selection of therapy . These are often - interrelated. The process of tissue assessm...

RISK MANAGEMENT Safety and risk management are priorities in the labora - tory . The use of warning labels helps to reduce the risk of contamination by transmissible infection, e.g. hepatitis B virus or human immunodeficiency virus (HIV). This is especially im...

SPECIMEN PROCESSING SPECIMEN PROCESSING SPECIMEN PROCESSING

Special stains A ‘special stain’ is a stain that is not routine, i.e. not an H&E stain. Immunohistochemical stains are conventionally separate from this category . Some special stains demonstrate normal substances in increased quantities or in abnormal locatio...

Specimen adequacy There are many reasons for an inadequate specimen. The operator may fail to sample the target organ or lesion or may take a sample that is too small to include or reveal a hetero geneous abnormality . A sample from the centre of a necrotic or...

Storage Resection specimens are generally stored for about 4–6 weeks. Tissue blocks and slides are retained for as long as space George Nicholas Papanicolaou , 1883–1962, Professor of Anatomy , Cornell University , New Y ork, NY , USA. Richard May , 1863–1936...

TISSUE SPECIMENS Routine tissue specimens received by a histopathology depart - ment include those intended for histopathological analysis and those for cytopathological assessment. These may overlap, and ‘cytology’ preparations sometimes undergo reprocessing ...

Cancer staging It is not su ffi cient simply to know what and where a cancer is; its extent must also be known. If it is localised, then locoregional treatments such as surgery and radiation therapy may be curative. If the disease is widespread then, although ...

End-of-life care End-of-life care is distinct from palliative care. Patients treated - palliatively may survive for many years; end-of-life care concerns the last few months of a patient’s life. Many issues, such as symptom control, are common to both palliati...