Common types of skin cysts
- Epidermoid cyst
Clinical presentation: They can occur anywhere on the body and present as skin colored dermal nodules sometimes having a central punctum. If they are infected they can be larger, erythematous and painful. Sometimes the do rupture spontaneously (Goldstein 2017).Patients with unusually high number of cysts in uncommon areas should raise suspicion of Gardener syndrome.
Pathophysiology: They arise from proliferation of epidermal cells in dermis, which can be transferred via trauma, infection, insect bite, or simple divisional process. Studies have shown HOV and UV light as cause of some epidermoid cysts (Fromm 2017).
Management: Asymptomatic cysts need not to be treated. Intralesional steroids can be given, however if the cyst is infected patient should be prescribed oral antibiotics. - Pilar cyst
Clinical presentation: Pilar cysts or trichilemmal cyst, is a keratin filled cyst arising from hair root sheath.
Pathophysiology: The squamous epithelium undergoes “trichilemmal keratinization” or rapid keratin formation without a granular cell layer, resulting in a cyst wall without a granular cell layer (Laumann 2017).
Pilar cyst vs epidermoid cyst (Kapadia 2017): Scalp is more commonly involved in pilar cyst. Central punctum is absent. Thick cyst wall which is less prone to rupture. Granular cell layer is absent.
Management: Removal is not necessary but if required surgical enucleation removal is preferred. - Chalazion
Clinical presentation: They usually present as swelling on the eye sometimes with erythema and pain if infected.
Pathophysiology: retained meibomian secretions cause granulomatous inflammation (Arbabi et al. 2010). Blockage of duct results in release of gland contents into surrounding soft tissue of eyelid and lipogranulomatous reaction (Carter 1998).
Management: antibiotics are not indicated since it’s a granulomatous process however if it shows signs of infection they can be prescribed. Usually they are self-limiting but sometimes a Intralesional steroid injection can help. Refractory lesions should be managed by ophthalmologist with incision and drainage and appropriate biopsy if required (Ghosh 2017).
References:
Arbabi et al. 2010. Chalazion. BMJ (Clinical research ed.) 341(aug04 1), p. c4044. doi: 10.1136/bmj.c4044.
Carter 1998. Eyelid disorders: diagnosis and management. American family physician 57(11), pp. 2695–702.
Fromm 2017. Epidermal Inclusion Cyst: Background, Pathophysiology, Epidemiology. Available at: https://emedicine.medscape.com/article/1061582-overview.
Ghosh 2017. Eyelid lesions – UpToDate. Available at: https://www.uptodate.com/contents/eyelid-lesions?source=search_result&search=chalazion&selectedTitle=1~15#H5.
Goldstein 2017. Overview of benign lesions of the skin – UpToDate. Available at: https://www.uptodate.com/contents/overview-of-benign-lesions-of-the-skin?source=search_result&search=epidermoid%20cyst&selectedTitle=1~73#H1101420445.
Kapadia 2017. Pilar cyst | DermNet New Zealand. Available at: https://www.dermnetnz.org/topics/pilar-cyst/.
Laumann 2017. Trichilemmal Cyst (Pilar Cyst): Background, Pathophysiology, Epidemiology. Available at: https://emedicine.medscape.com/article/1058907-overview#a5.
