24 Questions
What is the common route of metastasis for carcinomas?
Lymphatic channels
Which of the following tumours is known to metastasize late?
Renal Cell Carcinoma
What is the term for the formation of new blood vessels from existing ones in tumour growth?
Angiogenesis
What is the characteristic microscopic feature of epithelial tumours?
Acini, sheets, columns, cords, islands etc
What is the term for the study of the shape and structure of cells in tumour diagnosis?
Histomorphology
Which of the following is a characteristic feature of neoplastic cells?
Loss of polarity
What is the term for the spread of tumour cells through body cavities and natural spaces?
Trans-coelomic spread
Which of the following is an exception to the general rule of carcinoma spread through lymphatic channels?
Follicular Thyroid carcinoma
What is the primary way in which tumor cells spread to distant locations?
Metastasis
What is the term for the microscopic features of neoplasia?
Histomorphology
What is the role of growth factors in tumor growth?
Promoting tumor growth
What is the estimated global incidence of cancer in 2030?
21.4 million
Which of the following is NOT a characteristic of tumor cells?
Normal growth rate
What is the term for the process by which tumor cells invade and destroy surrounding tissues?
Local invasion
What is the leading cause of cancer mortality in developing countries?
Lung cancer
What is the relationship between the rate of tumor growth and the degree of differentiation?
Directly proportional
What is a characteristic of malignant tumours that distinguishes them from benign tumours?
They are irregular in shape and poorly circumscribed
How do malignant tumours spread?
Through local invasion and metastasis
What is a feature of normal cells that is lost in cancer cells?
Dependence on neighbouring cells for growth control
Why do cancer cells proliferate rapidly?
Because they disobey growth controlling signals
What is a characteristic of benign tumours?
They are spherical or ovoid in shape and well-circumscribed
What happens to normal tissues when malignant tumours invade?
They are infiltrated and destroyed
What is a way that malignant tumours can travel to distant sites?
Through tissue spaces and permeation of lymphatics
What is a difference between malignant and benign tumours in terms of their shape?
Malignant tumours are irregular, while benign tumours are spherical
Study Notes
Routes of Metastasis
- Lymphatic spread: common in carcinomas
- Hematogenous spread: common in sarcomas
- Spread along body cavities and natural spaces:
- Trans-coelomic spread
- Epithelium-lined surfaces
- Cerebrospinal fluid
- Implantation
- Exceptions: Cancers like RCC, HCC, and Follicular Thyroid carcinoma can spread to distant sites by hematogenous spread
Late Metastasizing Malignancies
- Renal Cell Carcinoma
- Salivary gland carcinoma
- Breast Carcinoma
- Carcinoid tumour
- Melanoma
- Granular cell tumour of the ovary
- Endometrial stromal sarcoma
Microscopic Features
- Microscopic patterns:
- Epithelial tumours: acini, sheets, columns, cords, islands
- Mesenchymal tumours: interlacing bundles, fascicles, whorls
- Histomorphology of neoplastic cells:
- Karyomegaly
- Loss of polarity
- Hyperchromatism
- Irregular nuclear margin
- Pleomorphism
- Anisonucleosis
- Increased nucleo-cytoplasmic ratio
- Tumour angiogenesis:
- Stimulation of new blood vessel formation from existing ones
Historical Background
- Cancer is not unique to humans, found in:
- Cnidaria (600 million years)
- Echinodermata (500 million years)
- Cephalopoda (500 million years)
- Amphibia (300 million years)
- Aves (150 million years)
- Never seen in Nematoda, Tradigrada, and Rotifera
Epidemiology of Cancer
- 2008 global cancer incidence: 12.7 million
- 2008 global cancer mortality: 7.6 million (21,000 deaths per day)
- 2030 predicted global cancer incidence: 21.4 million
- 2030 predicted global cancer mortality: 13.2 million
- Second leading cause of death globally (WHO)
- 70% of cancer mortality in developing countries
- Top 5 cancers in 2019: Breast, Lung, Prostate, Colorectum, and Stomach (GLOBOCAN 2020)
Characteristics of Tumours
- Rate of growth:
- Tumour cells proliferate more rapidly than normal cells
- Malignant cells grow more rapidly than benign ones
- Rate of growth dependent on degree of differentiation
- Cancer phenotype and stem cells:
- Cancer cells disobey growth controlling signals and proliferate rapidly
- Cancer cells are immortal by escaping death signals
- Cancer cells lose properties of differentiation
- Cancer cells develop newer mutations
- Cancer cells overrun neighboring cells and invade locally
Learn about the different routes of cancer metastasis, including lymphatic and hematogenous spread, and understand how different types of cancer spread through the body.
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