Naming tumours: -oma, carcinoma, sarcoma, and the misleading names !
- Topic
A tumour's name tells you its tissue of origin and whether it is benign or malignant, but a few famous names break the rules.
Updated 2026-11-01
What it is
Tumours are named after the cell they resemble and their behaviour. Benign tumours usually take the suffix -oma (adenoma, lipoma, leiomyoma); malignant epithelial tumours are carcinomas and malignant mesenchymal tumours are sarcomas. Knowing the exceptions (melanoma, lymphoma, mesothelioma, seminoma are all malignant) avoids a classic exam trap and a real communication error.
Key facts
- Every tumour has two parts: the neoplastic cells (parenchyma), which give the name and behaviour, and a supporting stroma of connective tissue and vessels.
- A dense, fibrous stroma (desmoplasia) makes some carcinomas stony hard, for example scirrhous breast and pancreatic cancers.
- Polyp describes a shape (a mass that projects above a mucosal surface), not a diagnosis; it may be an adenoma, a hyperplastic polyp or a carcinoma.
- Mixed tumours come from one clone that differentiates in two directions: the pleomorphic adenoma of the salivary gland is the classic example.
- Carcinomas are by far the most common malignant tumours in adults; leukaemias, lymphomas and myeloma are the haematolymphoid cancers.
Tissue of origin and the usual names
| Tissue | Benign | Malignant |
|---|---|---|
| Glandular epithelium | Adenoma (colon, thyroid, liver) | Adenocarcinoma |
| Surface (squamous) epithelium | Squamous papilloma | Squamous cell carcinoma |
| Fat | Lipoma | Liposarcoma |
| Smooth muscle | Leiomyoma (uterine fibroid) | Leiomyosarcoma |
| Skeletal muscle | Rhabdomyoma | Rhabdomyosarcoma |
| Bone / cartilage | Osteoma / chondroma | Osteosarcoma / chondrosarcoma |
| Blood vessels | Haemangioma | Angiosarcoma |
| Melanocytes | Melanocytic naevus | Melanoma |
| Lymphoid cells | No benign counterpart | Lymphoma, lymphoid leukaemia |
| Germ cells | Mature teratoma | Seminoma, embryonal carcinoma, immature teratoma |
Clinical notes
- Telling a patient that a ‘-oma’ is harmless can be wrong: always check whether the name is one of the malignant exceptions.
- A carcinoma of unknown primary is named only by its pattern (adenocarcinoma, squamous) until immunohistochemistry suggests the source.
Test yourself
Think of the answer, then tap the question to see it.
What is the malignant tumour of smooth muscle called?
Leiomyosarcoma; its benign counterpart is the leiomyoma (uterine fibroid).
Which four malignant tumours have names ending in -oma?
Melanoma, lymphoma, mesothelioma and seminoma (also hepatoma, an old name for hepatocellular carcinoma).
How does a hamartoma differ from a choristoma?
A hamartoma is a disorganised mass of tissue native to the site; a choristoma is normal tissue in an abnormal place, such as pancreatic tissue in the stomach wall.
What is a mixed tumour of the salivary gland?
A pleomorphic adenoma: one neoplastic clone that forms both epithelial and myxoid or cartilage-like stromal elements.
Related
- Benign vs malignant tumours: the comparison table
- Differentiation and anaplasia: how a tumour cell looks under the microscope
- Tumours of infancy and childhood
- Grading and staging: what TNM means
Related conditions
- Soft tissue sarcomas (liposarcoma, leiomyosarcoma, rhabdomyosarcoma)
- Melanoma
- Non-Hodgkin lymphoma
- Testicular cancer
- Hodgkin lymphoma
- Malignant pleural mesothelioma
- Hepatocellular carcinoma
- Ovarian germ-cell and sex cord–stromal tumours
- Parotid gland tumours
- Wilms tumour (nephroblastoma)
- Neuroblastoma
- Retinoblastoma
- Uterine fibroids (leiomyomas)
Elsewhere in DurgiPedia
- Epithelium: classification (the table to know)
- Connective tissue proper: cells and fibres
- Germ-layer derivatives: ectoderm, mesoderm, endoderm
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Tumor List | SEER Training (SEER Training Modules, National Cancer Institute, 2026); Cancer Classification (SEER Training Modules, National Cancer Institute, 2026); What Is Cancer? (National Cancer Institute (NCI), 2026).
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