What could be the cause of a 1 mm firm lump on my upper lip that feels like a small seed, is mobile, and is located near where my dentures (dental prosthetics) fit?

Mobile Firm Lump on Upper Lip Near Dentures

This is most likely a benign mucocele (mucous retention cyst) or a minor salivary gland lesion, given the small size (1 mm), mobile nature, seed-like consistency, and location near denture irritation—but you need clinical examination and possible excisional biopsy to definitively rule out other pathology.

Most Probable Diagnoses

Mucocele or Mucous Retention Cyst

• A 1 mm mobile, firm, seed-like lump in the upper lip is classically consistent with a mucocele, which results from trauma to minor salivary gland ducts (often from denture irritation or chronic biting) 1
• These lesions are typically mobile, well-circumscribed, and feel firm or rubbery on palpation 2
• The location near denture margins makes mechanical trauma a highly plausible etiology 1

Fibroma or Irritation Fibroma

• Chronic irritation from ill-fitting dentures commonly produces fibromas, which present as firm, mobile nodules 1
• These are benign mesenchymal proliferations that feel distinctly firm and seed-like 3

Less Common Possibilities

• Dermatofibroma: Rare on the lip but can present as a deep-seated, firm nodule 3
• Pyogenic granuloma: Usually larger, more vascular, and bleeds easily—less likely given your description 4
• Glomangioma: Extremely rare (only 13 reported lip cases), typically painful, but possible 5

What You Should Do

Immediate Assessment

• Examine denture fit: Check if dentures are creating pressure points or sharp edges at the exact location of the lump 1
• Assess for trauma signs: Look for adjacent mucosal irritation, erythema, or ulceration that would suggest chronic mechanical injury 1
• Evaluate mobility: Confirm the lump moves freely and is not fixed to underlying structures (fixed lesions raise concern for malignancy) 2

When to Seek Evaluation

• If the lump persists >2 weeks: Any oral lesion lasting beyond 2 weeks warrants specialist evaluation to exclude malignancy 6
• If it changes: Growth, color change, bleeding, or development of pain requires immediate assessment 2
• If denture adjustment doesn't resolve it: Remove the mechanical irritant first; if the lesion persists after denture modification, proceed to biopsy 1

Definitive Diagnosis

• Excisional biopsy is both diagnostic and therapeutic: For a 1 mm lesion, complete excision with histopathological examination provides definitive diagnosis and treatment 5, 3
• Simple excision under local anesthesia: This is straightforward for small lip lesions and allows pathological confirmation 4

Critical Red Flags to Rule Out

Signs That Demand Urgent Evaluation

• Fixation to underlying tissue: Mobile lesions are typically benign; fixed lesions raise malignancy concern 2
• Ulceration or bleeding: Spontaneous ulceration or bleeding suggests more aggressive pathology 4
• Rapid growth: Benign lesions grow slowly over months to years; rapid enlargement is concerning 2
• Associated systemic symptoms: Fever, night sweats, or weight loss could indicate lymphoma or systemic disease 2

Malignancy Considerations

• While a 1 mm mobile lesion is unlikely to be malignant, melanoma can occur on the lip vermilion and may initially appear as a small pigmented or non-pigmented nodule 7
• Any suspicious lesion on the lip requires biopsy, as early diagnosis dramatically improves outcomes for lip malignancies 7

Management Algorithm

1. Adjust or remove dentures for 2 weeks to eliminate mechanical irritation 1
2. If lesion persists: Schedule excisional biopsy with oral surgeon or dermatologist 5, 3
3. If lesion resolves: Ensure proper denture fit to prevent recurrence 1
4. If any red flags present: Proceed directly to biopsy without waiting 6

Common Pitfalls to Avoid

• Don't assume all small lip lumps are benign: Even small lesions require definitive diagnosis if they persist 6
• Don't delay biopsy for persistent lesions: The 2-week rule exists because early malignancy detection is critical 6
• Don't ignore denture-related trauma: Chronic irritation from ill-fitting dentures is a modifiable risk factor that must be addressed 1
• Don't use petroleum-based products chronically: These promote mucosal dehydration and increase infection risk 1