Pilar Cyst: Causes, Symptoms, Treatment & Complications 

Pilar cysts, also known as trichilemmal cysts, are common yet often misunderstood skin conditions. These cysts predominantly occur on the scalp and are generally benign. However, understanding their causes, symptoms, and treatment options is crucial for effective management. This article delves into the intricate details of pilar cysts, distinguishing them from sebaceous cysts, and exploring their pathology, treatment, and removal.

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What are Pilar Cysts?

A pilar cyst is a type of benign growth that arises from hair follicles, particularly from the outer root sheath. These cysts are filled with keratin, a protein that constitutes hair and nails. Pilar cysts are most commonly found on the scalp but can also occur in other areas of the body where hair follicles are present.

Pilar Cyst vs. Sebaceous Cyst

One common confusion is between pilar cysts and sebaceous cysts. While both are benign and can appear similar, they originate from different structures. Pilar cysts arise from the hair follicle's outer root sheath, whereas sebaceous cysts develop from sebaceous glands. Sebaceous cysts are filled with sebum, an oily substance, rather than keratin.

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Causes of Pilar Cysts

The exact cause of pilar cysts remains unclear, but several factors may contribute to their development.

Genetic Factors

Pilar cysts often run in families, suggesting a genetic predisposition. Studies indicate that mutations in the keratin gene may play a role in the formation of these cysts.

Trauma and Injury

Trauma to the scalp or other hairy regions can lead to the formation of pilar cysts. Injury may cause the hair follicle to malfunction, leading to cyst development.

Blocked Hair Follicles

When hair follicles become blocked, keratin can accumulate, resulting in a pilar cyst. This blockage can occur due to various reasons, including skin conditions and improper hair care.

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Symptoms of Pilar Cysts

Pilar cysts are generally asymptomatic but can present certain signs and symptoms that warrant attention.

Physical Characteristics

Pilar cysts are typically firm, round, and smooth to the touch. They are usually mobile under the skin and can range in size from a few millimeters to several centimeters.

Location and Number

These cysts are most commonly found on the scalp but can appear in other areas. Multiple cysts can develop simultaneously, particularly in individuals with a genetic predisposition.

Pain and Discomfort

While pilar cysts are generally painless, they can become painful if infected or inflamed. In such cases, the cyst may become red, tender, and swollen.

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Pathology of Pilar Cysts

Understanding the pathology of pilar cysts is essential for accurate diagnosis and treatment.

Histological Features

Under the microscope, pilar cysts exhibit a characteristic histological structure. They are lined by squamous epithelium, similar to the outer root sheath of the hair follicle, and are filled with homogenous, eosinophilic keratin.

Differential Diagnosis

Pathologists must differentiate pilar cysts from other cystic lesions, such as epidermoid cysts and dermoid cysts. Accurate diagnosis is crucial for appropriate treatment and management.

Treatment Options for Pilar Cysts

While pilar cysts are benign, treatment may be necessary for symptomatic relief or cosmetic reasons.

Observation and Monitoring

For asymptomatic pilar cysts, observation and monitoring may suffice. Regular follow-ups can help ensure that the cyst does not change in size or become symptomatic.

Surgical Removal

Surgical removal is the definitive treatment for pilar cysts. This procedure involves making an incision over the cyst, excising it, and ensuring complete removal to prevent recurrence. Surgical removal is typically performed under local anesthesia and has a high success rate.

Procedure Details

Minimally Invasive Techniques

Minimally invasive techniques, such as aspiration and laser therapy, are emerging as alternatives to traditional surgery. These methods aim to reduce scarring and recovery time but may not be suitable for all patients.

Antibiotics and Anti-inflammatory Medications

If the cyst is infected or inflamed, antibiotics and anti-inflammatory medications may be prescribed. These treatments can help reduce pain, swelling, and infection.

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Complications and Recurrence

While pilar cysts are generally benign, complications can occur.

Infection and Inflammation

Infection is a common complication, particularly if the cyst is traumatized. Infected cysts can become painful, red, and swollen and may require antibiotics or drainage.