Neoplasia I

• Neoplasm: Combination of the Greek words "neo" meaning ‘new’ and "plasma" meaning ‘formation’, literally translating to ‘new growth’
• Hyperplasia: Increased number of normal cells
• Neoplasia: Increased number of abnormal cells
• Hamartoma: Tumour-like malformation made up of an abnormal admixture of cells
• Benign neoplasms may be a developmental error or malformation rather than a neoplasm
• Benign neoplasms occur in different parts of the body, such as lung or liver, and are usually asymptomatic
• Benign neoplasms are usually well-circumscribed, often encapsulated, and rarely show hemorrhage and necrosis
• Benign neoplasms can sometimes become malignant over time due to the acquisition of additional genetic or epigenetic changes
• Benign neoplasms are usually asymptomatic but can present with incidental discovery on imaging, bleeding (rare), and other symptoms like hematemesis, hemoptysis, melaena, iron deficiency anemia, and mass effect
• The etiology of benign neoplasms is poorly understood, but it is similar to that of malignant neoplasms where the cells have not become abnormal enough to invade
• Pathologists play a crucial role in distinguishing between benign and malignant neoplasms through microscopical assessment of cell morphology and tissue architecture
• Malignant cells show characteristics like pleomorphism, hyperchromasia, increased mitotic activity, and an increased nuclear/cytoplasmic ratio
• Pathologists can also assess the extent of local invasion in malignant neoplasms
• Metastasis is the spread of malignant neoplasms from the primary site to a distant site, and surgery may not always be curative, requiring additional treatments like chemotherapy
• Metastasis is a multifactorial process that involves micro-metastasis, which may be clinically undetectable for months or years
• Tumour cells may remotely pre-condition a tissue site to enable subsequent colonization, known as the pre-metastatic niche
• Carcinoma is the most common type of cancer