Medical Care
Painful, swollen, erythematous, and/or purulent cysts may indicate the presence of infection. A wound culture with directed therapy may be necessary. [1]
Surgical Care
Definitive treatment is complete excision of the cyst. Several methods can be used to surgically remove these cysts. A small linear incision, an elliptical excision (see image below), and a circular dermal punch incision all are effective ways to remove the cysts. [24]
For all methods, the procedure involves the following steps:
Anesthetize the area with local anesthetic.
Over the center of the cyst, make a small linear incision, an elliptical excision, or a punch incision using a dermal punch biopsy tool.
Many times, the fibrous capsules of trichilemmal cysts are thick enough that the cyst can be removed intact via blunt dissection without expression of the contents. Alternatively, express the contents of the cyst, and then, using a curette, press against the inner wall, moving it back and forth to dislodge the outer side of the cyst from the surrounding tissue.
Grasp the edge of the cyst with forceps and separate the cyst wall from the surrounding connective tissue via blunt dissection.
Control the bleeding, and suture (as seen in the image below) or dress the wound as necessary.
If the cyst is ruptured or infected, deferring excision until the inflammation is reduced decreases the likelihood of spreading infection and wound healing problems. [1]
Most proliferating trichilemmal cysts are cured with complete surgical removal. [3] In the very occasional instances when multiple proliferating trichilemmal cysts require several local excisions, [8] additional radiotherapy and/or chemotherapy may be considered. [9]
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A firm, smooth swelling on the scalp.
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Surgical removal of an intact pilar cyst through an elliptical excision.
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Closure of the defect after surgical removal of the pilar cyst.
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The trichilemmal cyst is lined by a squamous epithelium without a granular layer and with swelling of the cells close to the cyst cavity, which is filled with homogenous keratin.
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At higher magnification, the cyst is lined by a squamous epithelium without a granular layer and with swelling of the cells close to the cyst cavity, which is filled with homogenous keratin.
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Numerous cholesterol clefts are identified within the homogenous keratin of the trichilemmal cyst.
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Pilar cyst, low power. The trichilemmal cyst is lined by squamous epithelium without a granular layer (trichilemmal keratinization) and with swelling of the cells close to the cyst cavity, which is filled with homogenous keratin. Calcifications are a common feature.
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Pilar cyst, medium magnification. Higher magnification shows the stratified squamous epithelium without a granular layer and shows swelling of the cells closest to the cyst cavity.
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Ruptured pilar cyst. A ruptured trichilemmal cyst showing replacement of the squamous lining by histiocytes and rare multinucleated giant cells.
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Ruptured, low power. Another ruptured trichilemmal cyst showing replacement of the epithelial lining by granulomatous reaction with numerous cholesterol clefts and calcifications.
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Ruptured, high power. Higher-power image highlighting the cholesterol clefts and calcifications.
