pilar cyst

WordNet

1. a closed sac that develops abnormally in some body structure
2. of or relating to a hair

PrepTutorEJDIC

1. 胞嚢(ほうのう)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/12/04 14:01:51」(JST)

wiki en

[Wiki en表示]

Trichilemmal cyst
Trichilemmal cyst. Note the thick durable white shell.
Classification and external resources
Specialty	dermatology
ICD-10	L72.1
ICD-9-CM	704.42
ICD-O	8103/0
DiseasesDB	29388

A trichilemmal cyst, also known as a wen, pilar cyst or isthmus-catagen cyst, is a common cyst that forms from a hair follicle. They are most often found on the scalp. The cysts are smooth, mobile and filled with keratin, a protein component found in hair, nails, skin, and horns. They are, however, clinically and histologically distinct from Trichilemmal Horns, which are much more rare and not limited to the scalp. Trichilemmal cysts may run in families and they may or may not be inflamed and tender, often depending on whether they have ruptured. Rarely, these cysts may grow more extensively and form rapidly multiplying trichilemmal tumors, also called proliferating trichilemmal cysts, which are benign but may grow aggressively at the cyst site. Very rarely, trichilemmal cysts can become cancerous.

Cause

Trichilemmal cysts are derived from the outer root sheath of the hair follicle. Their origin is unknown, but it has been suggested that they are produced by budding from the external root sheath as a genetically determined structural aberration. They arise preferentially in areas of high hair follicle concentrations, therefore, 90% of cases occur on the scalp. They are solitary in 30% of cases and multiple in 70% of cases.

Histologically, they are lined by stratified squamous epithelium that lacks a granular cell layer and are filled with compact "wet" keratin. Areas consistent with proliferation can be found in some cysts. In rare cases, this leads to formation of a tumor, known as a proliferating trichilemmal cyst. The tumor is clinically benign, although it may display nuclear atypia, dyskeratotic cells, and mitotic figures. These features can be misleading, and a diagnosis of squamous cell carcinoma may be mistakenly rendered.

Treatment

Surgical excision is required to treat a trichilemmal cyst. The method of treatment varies depending on the physician's training. Most physicians perform the procedure under local anesthetic. Others prefer a more conservative approach. This involves the use of a small punch biopsy about 1/4 the diameter of the cyst. The punch biopsy is used to enter the cyst cavity. The content of the cyst is emptied, leaving an empty sac. As the pilar cyst wall is the thickest and most durable of the many varieties of cysts, it can be grabbed with forceps and pulled out of the small incision. This method is best performed on cysts larger than a pea which have formed a thick enough wall to be easily identified after the sac is emptied. Small cysts have walls that are thin, and easily fragmented on traction. This increases the likelihood of cyst recurrence. This method often results in only a small scar, and very little if any bleeding.

See also

• Proliferating epidermoid cyst
• List of cutaneous conditions

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 皮膚の良性病変の概要 overview of benign lesions of the skin
• 2. 頭皮の発疹を有する患者へのアプローチ approach to the patient with a scalp disorder
• 3. 皮膚付属器癌 cutaneous adnexal tumors
• 4. 頭皮の蜂巣炎の郭清 dissecting cellulitis of the scalp
• 5. 皮膚石灰沈着症：病院および患者の評価 calcinosis cutis etiology and patient evaluation

English Journal

• Disseminated coccidioidomycosis masquerading as a ruptured epidermal inclusion cyst in a healthy young adult from Philadelphia.

• Farber SA1, Rubin AI2, Micheletti RG3.
• International journal of dermatology.Int J Dermatol.2015 Oct;54(10):e441-2. doi: 10.1111/ijd.12911. Epub 2015 Aug 12.
• PMID 26267257

• An intraosseous epidermal cyst developing in a metacarpal bone after K-wire fixation: a case report.

• Park IJ1, Kim HM, Lee JY, Park HW, Kang SH.
• Skeletal radiology.Skeletal Radiol.2015 Oct;44(10):1523-7. doi: 10.1007/s00256-015-2186-5. Epub 2015 Jun 12.
• Intraosseous epidermal cysts (IECs) are rare benign lesions caused by the proliferation of epidermal cells within the bone. The pathogenesis of IEC remains unclear; however, trauma-triggered infiltration of the bone by epidermal elements has been suggested. Here, we present a case of an IEC in the m
• PMID 26062836

Japanese Journal

• Facial Steatocystoma Multiplex Associated with Pilar Cyst and Bilateral Preauricular Sinus

• Journal of dermatology 29(3), 157-159, 2002-03-01
• NAID 10013980388

• 上唇に生じた孤立性毛包上皮腫の1例

• 日本口腔外科学会雑誌 45(4), 278-280, 1999-04-20
• NAID 10005074307

• 多発性 Pilar cyst

• 日皮会誌 107, 1019, 1997
• NAID 50004689809

Related Pictures

---

★リンクテーブル★

リンク元

「毛髪嚢腫」

「毛髪嚢腫」

　　[★]

英

pilar cyst

同

外毛根鞘嚢腫 trichilemmal cyst