The main part of the work of a histopathologist is concerned with the microscopic examination of tissues taken, either as biopsy samples (e.g. gastric biopsies) or resection specimens (e.g. mastectomy). These tissues are assessed macroscopically and material taken for microscopic examination for the purpose of diagnosis, prognosis and directing appropriate treatment. It is mainly of a problem-solving nature. There is a significant component of cytology which is the microscopic assessment of preparations of cells as aspirated or obtained from body tissues (e.g. fine needle aspirate of breast, pleural aspirate).