Naming and classifying tumours
How tumours are named and classified: by the normal cell they copy and by how they behave, the rules for benign tumours, carcinomas and sarcomas, the names that break the rules, and how the WHO classification sorts tumours today.
By the end, you can
- Explain why a tumour is named after the normal cell its cells resemble, not after its stroma or site.
- Apply the naming rules for benign tumours, carcinomas and sarcomas.
- Describe the other tumour families, including germ-cell, embryonal and mixed tumours.
- Recognise malignant tumours with benign-sounding names, and lesions that are not true neoplasms.
- Explain the behaviour categories (benign, intermediate, in situ, malignant) and what a modern classification combines.
What it is
A neoplasm (tumour) is an autonomous growth of cells descended from one altered cell. Tumours are classified by two questions: which normal cell the tumour cells resemble (their line of differentiation) and how the tumour behaves (benign, intermediate, in situ or malignant). The name usually encodes both: a leiomyoma is a benign tumour of smooth muscle, and a leiomyosarcoma is its malignant counterpart.
4 types to tell apart
- Epithelial tumours
- Benign: papillomas (from surfaces) and adenomas (glandular). Malignant: carcinomas, such as squamous cell carcinoma and adenocarcinoma.
- Mesenchymal tumours
- From fibrous tissue, fat, muscle, vessels, cartilage and bone. Benign names end in -oma (lipoma); malignant ones are sarcomas (liposarcoma).
- Haematolymphoid tumours
- From blood-forming and lymphoid cells: leukaemias, lymphomas and myeloma, all regarded as malignant.
- Other lines of differentiation
- Melanocytic (naevus, melanoma), neural and glial, mesothelial, germ-cell (teratoma, seminoma), embryonal (the -blastomas) and mixed tumours.
US spelling: tumours → tumors, tumour → tumor.
Normal function
Each tissue has its own cells
The body is built from four basic tissues. Epithelia cover surfaces, line tubes and form glands: a lining resists abrasion, while a lining secretes mucus and absorbs. Connective tissues (fibrous tissue, fat, cartilage, bone and vessels) develop from embryonic mesenchyme and support the epithelia from beneath the . Muscle and nervous tissue complete the set, and blood and lymphoid cells circulate through all of them.
Each cell type shows its job in its structure. Squamous cells make keratin and hold together by desmosomes; glandular cells make mucin and arrange themselves around a lumen; fibroblasts lay down collagen; fat cells store a single droplet of lipid. This differentiation is what a pathologist recognises under the microscope, and it is what tumour cells partly keep.
Underlying change · Step 1 of 5
A tumour: a clone of cells and its stroma
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Underlying change · Step 2 of 5
Naming by tissue of origin and behaviour
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Underlying change · Step 3 of 5
Tumour families beyond epithelium and mesenchyme
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 4 of 5
Names that break the rules, and look-alikes
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 5 of 5
Behaviour categories and the WHO classification
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .