neoplasia Flashcards
(40 cards)
What is Cancer?
Cancer is a disease caused by normal cells changing so that they grow in an uncontrolled way, invade surrounding tissue, and travel to other parts of the body (metastasis).
How is Cancer caused?
The origin of cancer, known as its aetiology, involves the accumulation of genetic alterations (e.g., mutations, deletions, translocations) and epigenetic changes (e.g., promoter methylation) in cells. These changes can be inherited or caused by external factors such as smoking, diet, UV irradiation, pollutants, viruses, or natural cell processes. These alterations result in abnormal (neoplastic) cell growth and tumor formation.
What does the term “tumour” refer to?
The term “tumour” is now commonly used as a synonym for “neoplasm” and refers to a swelling or new growth of abnormal cells.
What is neoplasia?
Neoplasia refers to the “new growth” of abnormal cells.
What are the two types of tumours?
Tumours are classified as either benign or malignant. Benign tumours are not harmful or life-threatening, while malignant tumours are life-threatening and considered “evil in nature.”
What is another term for cancer?
Cancer is synonymous with “malignant neoplasm” or “malignant tumour.” The term “cancer” has its roots in Latin, where it referred to a “crab” or “creeping ulcer.” In Greek mythology, “Karkinos” was a giant crab, and the swollen veins surrounding tumours were said to resemble the limbs of a crab.
How are tumours classified?
Tumours are classified based on their behaviour (benign or malignant) and histogenesis (cell or tissue of origin). Accurate classification of individual tumours is essential for accurate diagnosis, prognosis, and treatment.
What are the differences between benign and malignant tumours in terms of growth rate?
Benign tumours have a slow growth rate, while malignant tumours have a relatively rapid growth rate.
What is the difference in mitotic figures between benign and malignant tumours?
Mitotic figures, which are dividing cells, are rare in benign tumours but common in malignant tumours.
How do benign and malignant tumours differ in histological resemblance to normal tissue?
Benign tumours often have a good histological resemblance to normal tissue, while malignant tumours have a variable resemblance and often poor resemblance to normal tissue.
Do benign tumours invade surrounding tissues?
No, benign tumours do not invade surrounding tissues.
What about metastasis? Do benign tumours metastasize?
Benign tumours never metastasize, while malignant tumours frequently metastasize.
How do benign and malignant tumours differ in terms of their border?
Benign tumours typically have well-defined or encapsulated borders, whereas malignant tumours may have poorly defined or irregular borders.
Is necrosis (cell death) common in benign tumours?
No, necrosis is rare in benign tumours but common in malignant tumours.
What is the characteristic growth pattern of benign tumours on epithelial or mucosal surfaces?
When a benign tumour arises on an epithelial or mucosal surface, it grows away from the surface because it cannot invade. This often creates an exophytic lesion that grows outwards, forming either a pedunculated (stalked) or sessile (sitting on the surface) polyp.
What are some clinical problems that benign tumours can cause?
Although benign tumours are confined to their site of origin, they may cause clinical problems due to pressure on adjacent tissues, obstruction of fluid flow, hormone production, transformation into a malignant neoplasm, or anxiety in the patient.
How do malignant tumours behave on epithelial or mucosal surfaces?
Malignant tumours on epithelial or mucosal surfaces may initially form a protrusion, but eventually, they invade the underlying tissue, giving rise to an endophytic tumour that grows inwards. Ulceration is common in these cases.
How do malignant tumours behave in solid organs?
In solid organs, malignant tumours tend to have irregular margins, often with tongues of neoplastic tissue penetrating adjacent normal structures. They often show central necrosis due to inadequate vascular perfusion.
What are some of the issues associated with malignant tumours?
Malignant tumours are associated with significant morbidity and mortality due to pressure on and destruction of adjacent tissue, formation of secondary tumours (metastases), blood loss from ulcerated surfaces, obstruction of flow in certain organs, production of hormones leading to systemic effects, paraneoplastic effects causing weight loss and debility, as well as anxiety and pain.
What are the characteristics of borderline tumours?
Borderline tumours exhibit some features associated with malignancy, such as irregular architecture, nuclear stratification and pleomorphism, and increased mitotic activity. However, they lack the most important criterion of invasion. Their biological behavior, as determined by histology, is intermediate between that of clearly benign and overtly malignant tumours.
What is histogenetic classification of tumours based on?
Histogenetic classification of tumours is based on the tissue or cell of origin. It is determined through histopathological examination, which involves the microscopic study of biological tissues.
What is histology and how does it relate to gross anatomy?
Histology is the microscopic study of biological tissues. It is the microscopic counterpart to gross anatomy, which focuses on the study of organs and structures visible to the naked eye.
What is histopathology?
Histopathology is the microscopic study of diseased tissue. It involves examining tissue samples to identify any pathological changes or abnormalities.
How does histogenetic classification of tumours categorize them?
Histogenetic classification categorizes tumours based on the specific cell or tissue of origin, which is determined through histopathological examination. The tumour type is specified by the cell or tissue of origin and is incorporated into the tumour’s name. Major categories of origin include epithelial cells (forming carcinomas), connective tissues or mesenchymal tissues (forming sarcomas), haematopoietic system (forming leukaemias), and lymphatic system (forming lymphomas).
