Pathology Cheat Sheet
Behaviour Is the Point
Neoplasia behaviour for NEET-PG: benign vs malignant criteria, anaplasia, invasion, routes of metastasis, carcinoma vs sarcoma spread, and TNM staging.
MedNext Academy | 3 min read
Behaviour Is the Point
Neoplasia behaviour for NEET-PG: benign vs malignant criteria, anaplasia, invasion, routes of metastasis, carcinoma vs sarcoma spread, and TNM staging.
The definition and classification of neoplasia and the features that separate benign from malignant tumours, including invasion and metastasis.
High-yield lines
- A neoplasm is an autonomous abnormal mass of tissue whose growth exceeds and is uncoordinated with normal tissue and persists after the stimulus is removed.
- Benign epithelial tumours forming glands are adenomas, and those forming finger-like projections are papillomas.
- Malignant epithelial tumours are carcinomas and malignant mesenchymal tumours are sarcomas.
- The four criteria distinguishing benign from malignant tumours are differentiation, rate of growth, local invasion, and metastasis.
- Metastasis is the most reliable proof of malignancy in most solid tumours because benign tumours never metastasise.
- Anaplasia is loss of differentiation with pleomorphism, hyperchromasia, high nuclear-to-cytoplasmic ratio, and abnormal mitoses.
- Carcinomas typically spread by lymphatics while sarcomas typically spread by the bloodstream.
- Local invasion of the basement membrane and adjacent tissue distinguishes invasive carcinoma from carcinoma in situ.
- Seeding across body cavities is a route of spread seen in ovarian and gastric carcinoma.
- Benign tumours are usually well circumscribed and encapsulated, whereas malignant tumours are poorly demarcated and infiltrative.
- Grading assesses the degree of differentiation while staging assesses tumour size, nodal spread, and metastasis using the TNM system.
- Some benign tumours such as pleomorphic adenoma can recur after incomplete excision but still do not metastasise.
Mapped competency codes
- PA7.1
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This summary maps to PA7-neoplastic-disorders.
Frequently Asked Questions
Why is metastasis the most reliable marker of malignancy?
Because benign tumours never metastasise, so the presence of tumour deposits at a discontinuous distant site definitively indicates a malignant neoplasm in most solid tumours.
How do carcinomas and sarcomas differ in typical spread?
Carcinomas tend to spread through lymphatic channels to regional lymph nodes, whereas sarcomas tend to spread haematogenously through the bloodstream.
What is anaplasia?
Loss of structural and functional differentiation, marked by pleomorphism, nuclear hyperchromasia, a high nuclear-to-cytoplasmic ratio, and abnormal mitoses, and it is a hallmark of high-grade malignancy.
What is the difference between grading and staging?
Grading measures how differentiated a tumour is under the microscope, while staging measures its anatomical extent through tumour size, nodal involvement, and metastasis in the TNM system.
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