Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Trichilemmal Cyst (Pilar Cyst) Clinical Presentation

  • Author: Anne Elizabeth Laumann, MBChB, MRCP(UK), FAAD; Chief Editor: William D James, MD  more...
 
Updated: Apr 07, 2016
 

History

Trichilemmal cysts occur preferentially in areas with dense hair follicle concentrations; therefore, 90% occur on the scalp.[2] They may be seen infrequently on the face, neck, trunk, and extremities.[1, 2, 10]

Trichilemmal cysts are solitary in 30% and multiple in 70% of patients.[7]

Trichilemmal cysts may be red, swollen, and tender if they have ruptured or become infected.

A family history may be present because the condition can have an autosomal dominant pattern of inheritance.[4, 5] Proposed clinical criteria for recognizing autosomal dominant hereditary cases include the diagnosis of trichilemmal cyst in 2 or more first- or second-degree relatives, age of diagnosis younger than 45 years, and diagnosis of multiple or large (>5 cm) cysts or rare histologic features such as proliferating and ossifying cysts.[11]

A proliferating trichilemmal cysts presents as a slow-growing nodule.[5] They are more common in women, and occur at a mean age of 65 years.[2]

Rapid growth is unusual and may be a sign of infection or malignancy.[1] Other suspicious features include nonscalp location, size larger than 5 cm, and an infiltrative growth pattern.[2]

Next

Physical

Trichilemmal cysts manifest as skin-colored, smooth, mobile, firm, and well-circumscribed nodules,[1, 5] as shown in the image below.

A firm, smooth swelling on the scalp. A firm, smooth swelling on the scalp.

Ninety percent of trichilemmal cysts occur on the head, and 70% occur as multiple lesions.[2, 7]

Unlike epidermoid cysts, no punctum is seen.[2] If they are inflamed, they may be tender, erythematous, or both. The contents occasionally extrude to form a soft, cutaneous horn.

The wall of a marsupialized cyst may fuse with the overlying epidermis to form a crypt. This may occasionally discharge its contents and then self-resolve.

Previous
Next

Causes

If the cysts are hereditary, the inheritance pattern is autosomal dominant.[4, 5]  Hereditary trichilemmal cysts link to the short arm of chromosome 3.

Previous
 
 
Contributor Information and Disclosures
Author

Anne Elizabeth Laumann, MBChB, MRCP(UK), FAAD Professor of Dermatology, Chief of General Dermatology, Director of the Collagen Vascular Disorders Clinic, Northwestern University, The Feinberg School of Medicine

Anne Elizabeth Laumann, MBChB, MRCP(UK), FAAD is a member of the following medical societies: American Academy of Dermatology, Association of Professors of Dermatology, British Association of Dermatologists, Chicago Dermatological Society, Chicago Medical Society, Illinois Dermatological Society, Illinois State Medical Society, Medical Dermatology Society, Society for Investigative Dermatology, Women's Dermatologic Society

Disclosure: Nothing to disclose.

Coauthor(s)

Amanda Champlain, MD Clinical Research Fellow, Department of Dermatology, Northwestern University, The Feinberg School of Medicine

Amanda Champlain, MD is a member of the following medical societies: American College of Physicians, American Medical Association

Disclosure: Nothing to disclose.

Sapna M Amin, MD, FCAP Fellow in Dermatopathology, Department of Pathology, Northwestern University, The Feinberg School of Medicine

Sapna M Amin, MD, FCAP is a member of the following medical societies: American Society for Clinical Pathology, American Society of Dermatopathology, Chicago Dermatological Society, College of American Pathologists, Texas Society of Pathologists, United States and Canadian Academy of Pathology

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: American Medical Association, Alpha Omega Alpha, Association of Military Dermatologists, American Academy of Dermatology, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Phi Beta Kappa

Disclosure: Nothing to disclose.

Jeffrey Meffert, MD Associate Clinical Professor of Dermatology, University of Texas School of Medicine at San Antonio

Jeffrey Meffert, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, Association of Military Dermatologists, Texas Dermatological Society

Disclosure: Nothing to disclose.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

R Stan Taylor, MD The JB Howell Professor in Melanoma Education and Detection, Departments of Dermatology and Plastic Surgery, Director, Skin Surgery and Oncology Clinic, University of Texas Southwestern Medical Center

R Stan Taylor, MD is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Surgery, American Medical Association

Disclosure: Nothing to disclose.

Acknowledgements

Mohsin Ali, MBBS, FRCP, MRCP, MRCPI Consulting Staff, Department of Dermatology, Amersham General Hospital, UK

Disclosure: Nothing to disclose.

Marjan Mirzabeigi, MD Fellow in Dermatopathology, Department of Dermatology, Northwestern University

Marjan Mirzabeigi, MD is a member of the following medical societies: American Society for Clinical Pathology and College of American Pathologists

Disclosure: Nothing to disclose.

Jenneé A Rommel, MD Resident Physician, Combined Internal Medicine/Dermatology Residency Program, Washington Hospital Center, Georgetown University School of Medicine

Disclosure: Nothing to disclose.

References
  1. Thomas VD, Snavely NR, Lee KK, Swanson NA. Benign Epithelial Tumors, Hamartomas, and Hyperplasias. Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K, eds. Fitzpatrick's Dermatology in General Medicine. 8th ed. New York, NY: McGraw-Hill; 2012. 1334.

  2. James WD, Berger TG, Elston DM. Andrews’ Diseases of the Skin: Clinical Dermatology. 12th ed. Philadelphia, Pa: Saunders Elsevier; 2015. 673.

  3. Al-Khateeb TH, Al-Masri NM, Al-Zoubi F. Cutaneous cysts of the head and neck. J Oral Maxillofac Surg. Jan 2009. 67(1):52-7. [Medline].

  4. Leppard BJ, Sanderson KV, Wells RS. Hereditary trichilemmal cysts. Hereditary pilar cysts. Clin Exp Dermatol. 1977 Mar. 2(1):23-32. [Medline].

  5. Stone MS. Cysts. Bolognia JL, Jorizzo JL, Schaffer JV, eds. Dermatology. 3rd ed. St. Louis, MO: Saunders Elsevier; 2012. 1820-21.

  6. Weiss J, Heine M, Grimmel M, Jung EG. Malignant proliferating trichilemmal cyst. J Am Acad Dermatol. May 1995. 32(5 Pt 2):870-3. [Medline].

  7. Kirkham N. Tumors and Cysts of the Epidermis. Elder DE, Elenitsas R, Johnson BL, Murphy GF, Xu X, eds. Lever's Histopathology of the Skin. 10th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009. 801-3.

  8. Ivan D, Bengana C, Lazar AJ, Diwan AH, Prieto VG. Merkel cell tumor in a trichilemmal cyst: collision or association?. Am J Dermatopathol. 2007 Apr. 29(2):180-3. [Medline].

  9. Su W, Kheir SM, Berberian B, Cockerell CJ. Merkel cell carcinoma in situ arising in a trichilemmal cyst: a case report and literature review. Am J Dermatopathol. 2008 Oct. 30(5):458-61. [Medline].

  10. Melikoglu C, Eren F, Keklik B, Aslan C, Sutcu M, Zeynep Tarini E. Trichilemmal cyst of the third fingertip: a case report. Hand Surg. 2014. 19(1):131-3. [Medline].

  11. Seidenari S, Pellacani G, Nasti S, Tomasi A, Pastorino L, Ghiorzo P, et al. Hereditary trichilemmal cysts: a proposal for the assessment of diagnostic clinical criteria. Clin Genet. 2012 Oct 15. [Epub ahead of print]:[Medline].

  12. Abreu Velez AM, Brown VM, Howard MS. An inflamed trichilemmal (pilar) cyst: Not so simple?. N Am J Med Sci. 2011 Sep. 3(9):431-4. [Medline].

  13. Cotton DW, Kirkham N, Young BJ. Immunoperoxidase anti-keratin staining of epidermal and pilar cysts. Br J Dermatol. 1984 Jul. 111(1):63-8. [Medline].

  14. Hanau D, Grosshans E. Trichilemmal cyst with intrinsic parietal sebaceous and apocrine structures. Clin Exp Dermatol. 1980 Sep. 5(3):351-5. [Medline].

  15. Pusiol T, Morichetti D, Zorzi MG, Piscioli F. Ossifying trichilemmal cyst. Am J Dermpathol. Dec 2011. 33(8):867-8. [Medline].

  16. Mommers XA, Henault B, Aubriot MH, Trost O, Malka G, Zwetyenga N. Kystes trichilemmaux ossifiants multiples du cuir chevelu : un cas familial [Multiple ossifying trichilemmal cysts of the scalp: a familial case]. Rev Stomatol Chir Maxillofac. 2012 Feb. 113(1):53-6. [Medline].

  17. Mehrabi D, Leonhardt JM, Brodell RT. Removal of keratinous and pilar cysts with the punch incision technique: analysis of surgical outcomes. Dermatol Surg. 2002 Aug. 28(8):673-7. [Medline].

  18. Ibrahim AE, Barikian A, Janom H, Kaddoura I. Numerous recurrent trichilemmal cysts of the scalp: differential diagnosis and surgical management. J Craniofac Surg. Mar 2012. 23(2):e164-8. [Medline].

  19. Satyaprakash AK, Sheehan DJ, Sangueza OP. Proliferating trichilemmal tumors: a review of the literature. Dermatol Surg. 2007 Sep. 33(9):1102-8. [Medline].

 
Previous
Next
 
A firm, smooth swelling on the scalp.
Surgical removal of an intact pilar cyst through an elliptical excision.
Closure of the defect after surgical removal of the pilar cyst.
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.
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.
Numerous cholesterol clefts are identified within the homogenous keratin of the trichilemmal cyst.
Pilar cyst, low power. The trichilemmal cyst is lined by squamous epithelium with 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.
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.
Ruptured pilar cyst. A ruptured trichilemmal cyst showing replacement of the squamous lining by histiocytes and rare multinucleated giant cells.
Ruptured, low power. Another ruptured trichilemmal cyst showing replacement of the epithelial lining by granulomatous reaction with numerous cholesterol clefts and calcifications.
Ruptured, high power. Higher-power image highlighting the cholesterol clefts and calcifications.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.