# Introduction

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 surgical procedures, with visualisation of  cells, nuclei and tissue structure. Microscopic diagnosis was initially controversial, partly as a result of the ‘Kaiser’s cancer’ (a histological diag nosis by Virchow of  a non-malignant laryngeal lesion, after which Kaiser Friedrich III died of  laryngeal malignancy), but the medical and surgical community eventually accepted its value. Tissue analysis is now an integ ral and routine element of clinical practice. It is heavily dependent on microscopic assess ment, although newer methods of tissue analysis will increas ing ly provide additional information. Assessment of  tissue is usually the responsibility of  a histopathologist/cellular pathol ogist (a medically qualified practitioner), who depends on support from technical sta ff . In the UK, the sta ff responsible for tissue processing and the production of sections on glass slides are known as biomedical scientists (BMSs). The specialty variably known as Histopatholog y , Anatomic Pathology or Cellular Pathology encompasses histopathology , cytopathol ogy , autopsy work and molecular tissue diagnosis. Developments and changes in cellular pathology are con tinuous. The volume of  biopsies continues to increase as a result of  increasing clinical demands, expectations of  greater diagnostic precision, widespread flexible endoscopy and an ageing population with a higher pr evalence of  cancer and other illnesses. Cancer screening programmes also have an impact as they often depend heavily on cellular pathology . New techniques to refine histological assessment require addi tional resources. There is an increasing obligation to comply Rudolf  Ludwig Carl Virchow , 1821–1902, pathologist, Charité Hospital, Berlin, Germany , known as the ‘father of  modern pathology’. with national or international standards of  reporting, e.g. for cancer, and participation by pathologists in multidisciplinary team meetings is now routine rather than occasional. Other developments may reduce activity . Newer, less invasive meth - - ods may replace tissue analysis, e.g. human papilloma virus (HPV) testing for cervical pre-neoplastic lesions is replacing cytological assessment. New methods in imaging may reduce the need for tissue analysis. - The location of  a modern cellular pathology department is usually within or near a medium-sized or lar ge hospital or in a purpose-built o ff -site centre. Typically , more than 80% of specimens are from the gastrointestinal tract, gynaecological tract, skin or urological system. In line with clinical services, highly specialised work such as neuropathology takes place in - major regional centres. Consolidation of  clinical services may - result in reconfiguration of  relevant pathology services and molecular testing facilities. - 

To be aware of:
The principles of microscopic diagnosis
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The features of neoplasia
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The importance of clinicopathological correlation
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The role of additional techniques, including special stains,
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immunohistochemistry and molecular pathology