The two most common skin lumps are lipomas and sebaceous cysts. (epidermal cysts)
Lipomas are soft, fatty lumps that grow under your skin. They are harmless (benign) and do not usually need any treatment. Lipomas are common.
They are described as:
• feel soft and squishy
• can be anything from the size of a pea to a few centimetres across
• may move slightly under your skin if you press them (slip sign)
• are not usually painful
• grow slowly
Ironically, despite comprising of benign fat cells, losing weight will not cause lipomas to shrink like normal fat cells. Lipomas are of concern if they start to grow rapidly or are painful. Rapidly enlarging lipomas may be liposarcomas which are cancerous.
Lipomas can also enlarge slowly till they cause discomfort due to the size. Hence sometimes surgery may be recommended. The removed lipoma is usually sent for histology to confirm it is benign. Rarely, lipomas can be painful and this is called Dercum’s disease. Lipomas are removed as day surgery cases.
2. Sebaceous cysts (Epidermal cysts)
A sebaceous cyst is a sebum filled lump just underneath the skin. It’s common and harmless, and may disappear without treatment. Sebaceous cysts arise from sebaceous glands (which produce sebum and keratin) in the skin. When these glands get blocked but still continue to produce sebum, a cyst wall will form under the skin. Bacteria can infect and thrive on the sebum resulting in an infected sebaceous cyst which is enlarged, painful, red and filled with pus.
If a sebaceous cyst is infected, starting on antibiotics and anti-inflammatory drugs may help initially, however if does not improve over 24 to 48 hours, surgery is usually indicated. Sometimes just making a small incision to drain the pus will temporarily relieve the condition. However, because the cyst wall is not removed, these cysts can recur and get re-infected later. The definitive treatment is to remove the entire sebaceous cyst together with the cyst wall. That is the only way to ensure that the sebaceous cyst will not recur. Removal of sebaceous cysts are done as day surgery cases.