Is My Lipoma a Cyst?

Lipoma is not a cyst. Lipoma is a cluster of overactive fat cells, which formed in together and appeared as a lump. Cyst is a different entity. A cyst is an enclosed tumor/lump which contains fluid. There are so many types of cysts that can occur in the body and it can occur at any place in the body even in internal structures. There can be several causes for the development of a cyst

Blockage of ducts
Infections
Genetic conditions
Errors in the embryonic development
Trauma
Chronic inflammatory conditions

Most of cysts are benign and occur due to a blockage of a duct that drains the fluid.

Lipoma and a cyst may look similar most of the time but there are features that can distinguish lipoma from a cyst.

Let us see what the features in a lipoma are and what the features in a cyst are. This will help you understand what a lipoma is and how it differentiates from a cyst.

Features	Lipoma	Cyst
Symptoms	Mostly asymptomatic or patient may notice a lump. Sometimes the lump can be painful.	Mostly asymptomatic or patient may notice a lump. Sometimes painful.
Site	Commonly occurs in the upper limb, neck, shoulders, upper thighs and the back.	Can occur at any place in the body. Even in internal organs
Shape	Lipomas are usually spherical, but some lipomas can be discoid or hemispherical. Lipomas are not tensed.	Most are tensed and spherical, bulging outwards, stretching the overlying skin.
Size	Size can vary, usually it’s less than 2 cm. Lipomas more than 5 cm are called giant lipomas.	Size can vary from few millimeters to few centimeters
Surface	The surface feels smooth and soft and lobulated. No punctum seen.	Surface is smooth. A central pore or punctum may tether the cyst to the overlying epidermis in some types of cyst and a thick discharge can sometimes be expressed. Indentation is present (on compression of the lump, the depression remains for some time)
Edge	Edge is not circular it appears irregular corresponding to each lobule. Slipping sign is present which is when you try to hold the lump it slips away from your fingers.	Well defined, regular and easy to feel. Slipping sign is not present.
Color	The skin that overlies the lump is normal. No skin discoloration or spots seen.	The skin over the cyst has a bluish tinge with a punctum or pit visible Which is a dark color spot on the overlying skin.
Tenderness	Usually not tender, but if it involves the deep structures like blood vessels, nerves or muscles it can be painful.	Uncomplicated cysts are not painful. If there is pain and tenderness that means there is an infection.
Temperature	The temperature of the skin over a cyst is normal	The temperature of the skin over a cyst is normal except when the cyst is infected.
Consistency	Soft	Firm
Transillumination (In a dark room, a bright, thin pencil torch is placed on the lump, from behind, so the light is shining through the lump towards your eye. If the lump glows red it is said to transilluminate)	May or may not transilluminate	Does not transilluminate

Conclusion

Lipoma is not a cyst. Lipoma consists of fat cells whereas a cyst is a lump that contains fluid. The main features to differentiate lipoma form a cyst is that lipoma is spherical, not tensed, the edges are irregular, slipping sign is present, the surface is smooth, soft and lobulated, no punctum, soft in consistency, fluctuation and transillumination may or may not be present. Whereas the a cyst is spherical and tensed, with well-defined regular margins, the color overlying skin has a bluish tinge, a punctum is present, indentation is present, firm in consistency, non-fluctuant and does not transilluminate.

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Is My Lipoma a Cyst?