Which of the following is true about Marjolin's ulcer?

Marjolin's ulcer may develop in: 1. Post burn scar 2. Chronically discharging osteomyelitis sinus 3. Long standing venous ulcer 4. Chronic ulcer due to trauma 5. Post radiation ulcer Characteristic features Slow growing as scar tissue is relatively avascular. Painless as there is no nerve in the scar tissue. No secondary deposits in the regional lymph node , as there is no lymphatic spread. Radioresistant due to avascularity. If ulcer invades the normal tissue , then only lymph node may be involved by lymphatic spread.