Histopathological examination is a microscopic examination of tissue material taken from a patient to assess the nature of the disease process. The material for the histopathological examination is usually taken during the patient's operation (this is then referred to as intraoperative sampling) or by biopsy. The histopstological examination makes it possible to diagnose cancer, distinguishing between benign and malignant tumours. In addition, it makes it possible to diagnose various inflammatory and degenerative diseases. Histopathological diagnosis is essential to assess the monitoring of treatment progress.