Podcast
Questions and Answers
What is the hallmark feature of anaplastic tumours?
What is the hallmark feature of anaplastic tumours?
Loss of tissue architecture and specialized functional activity
What is nuclear pleomorphism?
What is nuclear pleomorphism?
Variation in shape and size of nuclei
What is the normal nucleo-cytoplasmic ratio, and how does it change in malignant cells?
What is the normal nucleo-cytoplasmic ratio, and how does it change in malignant cells?
Normal ratio is 1:4 or 1:6, but it approaches 1:1 in malignant cells due to nuclear enlargement
What is the significance of abundant mitoses in tumour cells?
What is the significance of abundant mitoses in tumour cells?
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What role do hormones play in tumour growth?
What role do hormones play in tumour growth?
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What is the difference in growth rate between benign and malignant tumours?
What is the difference in growth rate between benign and malignant tumours?
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What is the significance of tumour giant cells?
What is the significance of tumour giant cells?
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What is metastasis, and which type of tumours can metastasize?
What is metastasis, and which type of tumours can metastasize?
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What is the usual fate of benign and malignant tumours if left untreated?
What is the usual fate of benign and malignant tumours if left untreated?
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Why do benign tumours rarely recur after excision, whereas malignant tumours often do?
Why do benign tumours rarely recur after excision, whereas malignant tumours often do?
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Study Notes
Neoplasia
- Neoplasia means a new growth, and the new growth is called a neoplasm
- In clinical practice, a neoplasm is often called a tumor, although tumor refers to all types of swellings, not just neoplasms
- Oncology is the science of studying neoplasms
- Cancer is the common term for all malignant tumors
Definition of a Neoplasm
- A neoplasm is an abnormal new growth of cells independent of physiologic growth stimuli (autonomous)
- It serves no useful purpose and its growth is uncoordinated with that of the surrounding tissue
- Its growth persists after cessation of the stimuli that provoked its formation
Classification of Neoplasms
- Neoplasms are classified according to their clinical behavior into:
- Benign
- Malignant
- Classification is also based on the origin of the tumor, including:
- Epithelial origin
- Mesenchymal origin
- Germ cell origin
Characteristics of Benign and Malignant Tumors
- Capsulation:
- Benign tumors: grow by expansion, with formation of a fibrous capsule, and have a plane of cleavage around the tumor
- Malignant tumors: grow by infiltration, destroy and penetrate the surrounding tissue, and do not develop a capsule
- Differentiation and anaplasia:
- Benign tumors: composed of well-differentiated cells that resemble normal counterparts
- Malignant tumors: characterized by a wide range of parenchymal differentiation, from well-differentiated to undifferentiated
- Anaplasia implies dedifferentiation or loss of structural and functional differentiation of normal cells
- Rate of growth:
- Most benign tumors grow slowly over a period of years
- Most cancers grow rapidly, spread locally and to distant sites (metastases), and eventually kill their host
- Metastasis:
- Marks a tumor as malignant
- Malignant tumors can metastasize, with few exceptions
- Recurrence after excision:
- Usually occurs in malignant tumors
- Fate:
- Benign tumors: not fatal unless present in a vital area
- Malignant tumors: usually fatal if not diagnosed early and treated adequately
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Description
Learn about neoplasia, neoplasm, tumors, and oncology. Understand the difference between tumor and neoplasm, and the definition of cancer.
