Aphthous ulcers and reactive oral lesions
- Lesion
Common benign mouth lesions: painful shallow ulcers (canker sores) and lumps that grow in response to irritation or injury.
What it is
Most oral lumps and ulcers are reactive, not neoplastic. Aphthous ulcers are common, recurrent and painful, of unknown cause, sometimes linked to systemic disease. Reactive growths form where trauma or irritation keeps stimulating repair: the irritation fibroma, pyogenic granuloma, peripheral ossifying fibroma and peripheral giant cell granuloma. All are treated by excision but must be separated from malignancy.
Structure
- Aphthous ulcer: ulcer with fibrinopurulent membrane; early mononuclear infiltrate, later neutrophils at the base.
- Fibroma: nodular mass of collagen covered by stratified squamous epithelium.
- Pyogenic granuloma: highly vascular lobular proliferation of capillaries in edematous stroma with inflammation (it is neither pyogenic nor a granuloma).
- Giant cell granuloma: aggregates of foreign-body-like giant cells in a fibroangiomatous stroma.
Step by step
- Repeated minor trauma (biting, dentures, calculus) or hormonal stimulation provokes repair.
- Granulation tissue forms with abundant new capillaries (pyogenic granuloma).
- The granulation tissue may mature into dense fibrous tissue (fibroma) or deposit mineralised matrix (ossifying fibroma).
- In aphthous ulcers an immune reaction against the mucosa, influenced by genetics, stress and nutrition, produces focal necrosis.
Reactive gingival and mucosal lumps
| Lesion | Look | Microscopy | Who |
|---|---|---|---|
| Irritation fibroma | Firm pink nodule, bite line | Dense collagen | Any adult |
| Pyogenic granuloma | Red-purple, ulcerated, bleeds | Lobular capillaries, granulation tissue | Children, young adults, pregnancy |
| Peripheral ossifying fibroma | Red ulcerated gingival nodule | Fibrous tissue with bone or cementum | Young women |
| Peripheral giant cell granuloma | Gingival mass | Multinucleated giant cells | Any age |
Clinical notes
- Aphthous ulcers heal in one to two weeks; persistent, large or atypical ulcers need biopsy to exclude cancer, infection or Behçet disease.
- Pyogenic granulomas of pregnancy often regress after delivery.
- Any oral ulcer lasting more than about three weeks should be biopsied.
Test yourself
Think of the answer, then tap the question to see it.
What is a pyogenic granuloma under the microscope?
A highly vascular proliferation of granulation tissue (lobular capillaries) with inflammation; it contains neither pus nor granulomas.
Which systemic diseases are associated with recurrent aphthous ulcers?
Celiac disease, inflammatory bowel disease and Behçet disease.
Which lesion must be distinguished from a peripheral giant cell granuloma?
Central giant cell lesions of the jaw and the brown tumours of hyperparathyroidism.
Connections
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: Mouth Disorders (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.