Sebaceous cyst
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- When an opening of one sebaceous glands becomes blocked, it distends with sebum, and becomes a sebaceous cyst.
History
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- Duration - present for some years
- Symptoms - Multiplicity often multiple
Examination
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- Site - They are found in the hairy parts of the body. The scalp, scrotum, neck are the common sites. NB: No sebaceous glands on the palms and soles.
- Shape and size - Tense and spherical.
- Surface is smooth.
- Edge is well defined.
- Colour is usually normal. 1/2 of the time ‘punctum’ a dark spot is visible.
- Tenderness - are not tender.
- Temperature is normal.
- Composition Most feel hard and solid.
- Fluctuation - Not possible to elicit fluctuation when its tense.
- NB: There should be firm underlying tissue to press them against to elicit fluctuation.
- Transilluminate - They do not transilluminate because they are full of sebum.
- Relations - All sebaceous cysts are attached to the skin. Not attached to underlying structure.
- Lymph drainage - Normal.
A sebaceous horn
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- Slowly exuding sebum through a large punctum hardening into a conical spike.
- A sebaceous horn can therefore only grow if the patient fails to wash!
Cock’s peculiar tumour
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- Cock’s peculiar tumour is an infected, open, granulating, oedematous sebaceous cyst.
- Malignant looking. So it is often mistaken for a squamous cell carcinoma of the scalp.
- Has everted edge.