Sebaceous cyst


Epidermal cyst, giant comedo, epidermoid inclusion cysts are alternative names.

Sebaceous cyst


Sebaceous cysts originate from sebaceous glands and which contain sebum, are relatively rare and are known as steatocystoma simplex or, if multiple, as steatocystoma multiplex.


The term is still often used for epidermoid and pilar cysts.


The scalp, ears, back, face, and upper arm, are common sites of sebaceous cysts, 


They  may occur anywhere on the body except the palms of the hands and soles of the feet. 


They are more common in hairier areas.


In cases of long duration such cysts  could result in hair loss on the skin surface immediately above the cyst. 


They are  generally round in shape.


They are generally mobile masses.


They may contain fibrous tissues and fluids.


A fatty substance that may be present resembles cottage cheese, in which case the cyst may be called keratin cyst.


It is a “cheesy”, viscous, serosanguineous fluid.


With surgery, a cyst can be excised in its entirety. 


High levels of testosterone and the use of androgenic anabolic steroids will cause such cysts.


Hereditary causes of sebaceous cysts include Gardner’s syndrome and basal cell nevus syndrome.


About 90% of pilar cysts occur on the scalp, with the remaining sometimes occurring on the face, trunk and extremities.


Pilar cysts are significantly more common in females, and a tendency to develop these cysts is often inherited in an autosomal dominant pattern.



In most cases, multiple pilar cysts appear at once.


Sebaceous cysts generally do not require medical treatment. 


If they continue to grow, become unsightly, painful, infected, or all of the above surgery is required.


Surgical excision of a sebaceous cyst completely removes the sac and its contents.


If the cyst wall can be removed in one piece, the cure rate is 100%, and if it is fragmented the cyst may recur. 


An infected cyst may require oral antibiotics.


A collection of white keratinous and sebaceous material contained in a cyst wall which is lined with squamous epithelium which produces keratin.

Keratin accumulates inside the cyst and forms a mass that can reach several centimeters in size and usually opens to the skin through a keratin filled blackhead orifice.

Can occur on the face, ears, chest or back.

Occurs in areas where sebaceous glands are numerous or are large such as on the labia and scrotum.

When lesions are extensive on the face or in unusual areas may part of the Gardner’s syndrome.

May originate from comedones from occlusion of pilosebaceous orifices.

May be a result of traumatic implantation of epidermal epithelium or of embryonic origin.

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