science

Epidermoid cyst

Epidermoid cyst is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Epidermoid cyst rather than just read about it. In short: An epidermoid cyst or epidermal inclusion cyst is a benign cyst usually found on the skin. The cyst develops out of ectodermal tissue.

Key takeaways

Epidermoid cyst belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Epidermoid cyst to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Epidermoid cyst from memory before moving on to harder problems.

Reference excerpt

An epidermoid cyst or epidermal inclusion cyst is a benign cyst usually found on the skin. The cyst develops out of ectodermal tissue. Histologically, it is made of a thin layer of squamous epithelium.

Signs and symptoms The epidermoid cyst may have no symptoms, or it may be painful when touched. It can release macerated keratin. In contrast to pilar cysts, epidermoid cysts are usually present on parts of the body with relatively little hair. Some vaginal cysts are epidermoid cysts. Although they are not malignant, there are rare cases of malignant tumors arising from an epidermoid cyst. Epidermal inclusion cysts account for approximately 85–95% of all excised cysts; malignant transformation is exceedingly rare. The incidence of squamous cell carcinoma developing from an epidermal inclusion cyst has been estimated to range from 0.011 to 0.045%.

Diagnosis Epidermoid cysts are usually diagnosed when a person notices a bump on their skin and seeks medical attention. The definitive diagnosis is made after excision by a pathologist based on microscopic appearance of a cystic lesion lined by cornified epithelium containing lamellated keratin without calcifications. They can also be seen as isointense lesions on MRI or hyperintensities on FLAIR.

Treatment Cysts can be removed by excision. In case of fronto-ethmoidal epidermoid cysts, surgical resection appears to be the mainstay of treatment; however, the extent of resection is dictated by adherence of the tumor capsule to the surrounding vital structures. Hydrogen peroxide gel (H2O2) was previously recommended for cyst treatment, particularly those on body piercings. However the gel cannot adequately permeate the cyst and was not found to be effective. Hydrogen peroxide is no longer recommended for wound care by doctors as it can damage the healing tissues. On body piercings, self treatment with a hot saline soak to help drain the cyst and the use of an antibacterial or medicated talcum powder to help dry out the bump and reduce bacterial proliferation is generally recommended until medical advice can be obtained. (Use of talc is no longer recommended due to recently discovered associations with multiple cancers.) Piercings, however, are more likely to be victims of hypertrophic scarring than a cyst. Cheek piercings seem to be the piercing most prone to cysts due to the possible interruption of saliva ducts.

Terminology Several synonyms exist for epidermoid cysts, including epidermal cyst, infundibular cyst, keratin cyst and epidermal inclusion cyst Epidermal inclusion cyst more specifically refers to implantation of epidermal elements into the dermis. The term infundibular cyst refers to the site of origin of the cyst: the infundibular portion of the hair follicle. The majority of epidermal inclusion cysts originate from the infundibular portion of the hair follicle, thus explaining the interchangeable, yet inaccurate, use of these two terms. Epidermoid cyst may be classified as a sebaceous cyst, although technically speaking it is not sebaceous. "True" sebaceous cysts, cysts which originate from sebaceous glands and which contain sebum, are relatively rare and are known as steatocystoma simplex or, if multiple, as steatocystoma multiplex. Medical professionals have suggested that the term sebaceous cyst be avoided since it can be misleading. In practice, however, the term is still often used for epidermoid and pilar cysts.

Additional images

See also Intracranial epidermoid cyst List of cutaneous neoplasms associated with systemic syndromes Proliferating epidermoid cyst Verrucous cyst

References

External links

DermNet lesions/cysts

Illustrations

Worked examples

Example 1 — a first encounter with Epidermoid cyst

Start with the simplest possible case. Write down what Epidermoid cyst claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Epidermoid cyst before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Epidermoid cyst ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Epidermoid cyst

In research: Epidermoid cyst appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Epidermoid cyst in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Epidermoid cyst is common in secondary-school and first-year university syllabi. It links to neighbouring topics Conditions of the skin appendages, Epidermal nevi, neoplasms, and cysts, so understanding it makes those chapters shorter.
In everyday life: Look for Epidermoid cyst outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Epidermoid cyst in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Epidermoid cyst means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Epidermoid cyst out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Epidermoid cyst in simple terms?

An epidermoid cyst or epidermal inclusion cyst is a benign cyst usually found on the skin. The cyst develops out of ectodermal tissue.

Why does Epidermoid cyst matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Epidermoid cyst?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Epidermoid cyst.