Question 1

I have a small clear bump near my fingernail that comes and goes—my GP said it's a mucous cyst and suggested I just leave it alone. Should I be worried it's something more serious like cancer?

Accepted Answer

Reassuring answer: mucous cysts are completely benign (not cancerous) and your GP's advice to leave it alone is appropriate if it's not bothersome. Here's why you can be confident in this diagnosis: CHARACTERISTIC FEATURES: Mucous cysts have a very typical appearance that experienced doctors recognize on sight: (1) Location—always near fingernail, usually on back (dorsal) surface of finger at DIP joint; (2) Appearance—translucent or clear, dome-shaped, 3-10mm size, soft to touch; (3) Transillumination—if doctor shines light through cyst, it glows clear (solid tumors don't do this); (4) Associated arthritis—X-rays show arthritis in nearby DIP joint. BENIGN NATURE: Mucous cysts are simply pockets of joint fluid (synovial fluid and mucin) that leak from arthritic DIP joint through small defect in joint capsule. They're essentially a 'herniation' of joint lining, similar to how inner tube pokes through tire. Not precancerous, not related to any malignancy. COMES AND GOES: The fact yours fluctuates in size is actually reassuring and typical of mucous cysts. When arthritis flares or you use finger more, cyst fills with more fluid and enlarges. When inflammation settles, cyst may shrink or even temporarily disappear. Cancerous masses typically grow steadily, don't fluctuate. WHEN TO WORRY: If bump has unusual features—solid rather than fluid-filled, rapidly growing (doubling in size over days/weeks), painful without trauma, located away from joint, or looks different from typical cyst description—then further evaluation needed. But classic mucous cyst as you describe is harmless. TREATMENT OPTIONS: You can leave it alone (reasonable if not bothersome), have it aspirated (drained with needle—gives temporary relief but often recurs), or have it surgically removed (85-90% permanent cure). Choice depends on how much it bothers you. Many people live with them for years without problems.

Question 2

My mucous cyst has caused a groove down my fingernail that looks terrible—if I have the cyst removed, will my nail go back to normal?

Accepted Answer

Honest answer: nail groove MAY improve after cyst removal but often doesn't completely resolve, especially if you've had the cyst for a long time. Here's what determines nail outcome: HOW CYST CAUSES NAIL DEFORMITY: Mucous cyst sits right next to nail bed (the tissue under nail that produces nail). When cyst presses on nail bed, it prevents that section of nail bed from producing normal nail. The result is a longitudinal groove (running length of nail) where cyst compresses nail bed. Nail grows continuously from base, so groove appears to 'move' down nail as nail grows out (takes 3-4 months for entire fingernail to grow out and replace itself). NAIL RECOVERY AFTER CYST REMOVAL: If cyst removed surgically: (1) First 3-4 months—nail that was already growing when cyst removed will still have groove (because that nail was formed while cyst was present). You'll see groove gradually 'move' down nail and eventually grow off end of finger; (2) After 3-4 months—new nail growing from base should be normal if cyst permanently gone and nail bed recovers; (3) However—if cyst was present for months or years, nail bed may be permanently damaged (scarred, atrophied) and continue producing abnormal nail even after cyst removed. This happens in 20-30% of long-standing cysts. REALISTIC EXPECTATIONS: Recent cyst (present less than 6 months)—nail likely returns to normal after removal. Longstanding cyst (present 1-2+ years)—nail may improve but groove often persists to some degree. Very longstanding cyst (5+ years)—permanent nail deformity likely even after cyst removed. SURGICAL TECHNIQUE MATTERS: If surgeon needs to temporarily remove part of nail to access and remove cyst fully, nail regrows normally (nails regenerate well). The key is removing the cyst and underlying bone spur completely to prevent recurrence—if cyst comes back, nail deformity will return. WHAT TO DO: If nail deformity bothers you cosmetically, surgical excision is best option (85-90% cure rate, nail has best chance of recovering). Just be realistic that improvement not guaranteed, especially if you've had cyst for years. Some patients choose to live with groove rather than have surgery. Your hand surgeon can assess your specific situation and give more tailored prediction based on cyst duration and nail bed appearance.

Medical Disclaimer

Finger Cyst from Arthritis (Mucous Cyst)

📖What is Finger Cyst from Arthritis (Mucous Cyst)?

🔬What Causes It?

⚠️Risk Factors

You may be at higher risk if:

🛡️Prevention