Not all cysts are dangerous, but some can be harmful depending on their location, size, and potential to become malignant or cause complications. Here are some potentially dangerous cysts:

1. Cancerous or Precancerous Cysts

• Ovarian Cysts (some types)
  • Dermoid cysts (mature cystic teratomas) – Rarely cancerous but can grow large and cause complications.
  • Cystadenomas (serous/mucinous) – Can become very large and, in rare cases, malignant.
  • Endometriomas – Associated with endometriosis; can affect fertility.
  • Malignant ovarian cysts – Some ovarian cysts may be cancerous, especially in postmenopausal women.
• Pancreatic Cysts
  • Mucinous cystic neoplasms (MCNs) & Intraductal papillary mucinous neoplasms (IPMNs) – Can progress to pancreatic cancer.
• Thyroid Cysts (if suspicious nodules)
  • Some complex thyroid cysts may harbor cancerous cells.
• Renal (Kidney) Cysts
  • Complex renal cysts (Bosniak III/IV) – May be cancerous or require surgical removal.

2. Cysts That Can Cause Serious Complications

• Brain Cysts (e.g., Arachnoid or Colloid Cysts)
  • Can increase intracranial pressure, leading to headaches, seizures, or hydrocephalus.
• Baker’s Cyst (Popliteal Cyst)
  • If ruptured, can mimic deep vein thrombosis (DVT) and cause severe swelling.
• Hepatic (Liver) Cysts (e.g., Hydatid Cysts or Polycystic Liver Disease)
  • Hydatid cysts (from Echinococcus tapeworm) can rupture, causing anaphylaxis or spread infection.
• Breast Cysts (Complex or Solid Components)
  • May require biopsy to rule out breast cancer.
• Pilonidal Cysts
  • Can become infected, leading to abscesses and chronic sinus tracts.
• Ganglion Cysts (if pressing on nerves)
  • Rarely dangerous but can cause nerve compression (e.g., in the wrist).

3. Infected or Ruptured Cysts

Any cyst (even benign ones like epidermoid cysts) can become infected or rupture, leading to:

• Severe pain
• Abscess formation
• Systemic infection (sepsis in rare cases)

When to Worry?

See a doctor if a cyst:
✔ Grows rapidly
✔ Causes severe pain
✔ Changes in appearance (redness, warmth)
✔ Is associated with weight loss, fever, or other systemic symptoms
✔ Is located in a critical area (brain, pancreas, ovaries)

Most cysts (like simple ovarian, sebaceous, or ganglion cysts) are benign and harmless, but medical evaluation (ultrasound, MRI, biopsy) may be needed if there’s concern. Would you like details on a specific type?