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Dermatology > BENIGN NEOPLASMS
Folliculoma
Article Last Updated: Oct 5, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 9  
Author: Craig G Burkhart, MD, MPH, Clinical Professor, Department of Medicine, Clinical Assistant Professor, Department of Dermatology, Section of Dermatology, Medical College of Ohio at Toledo, Ohio University School of Medicine
Craig G Burkhart is a member of the following medical societies: American Academy of Dermatology, Ohio State Medical Association, and Phi Beta Kappa
Coauthor(s):
Craig Nathaniel Burkhart, MD, MS, Staff Physician, Dermatology, University of NC at Chapel Hill
Editors: Terry L Barrett, MD, Director, Associate Professor, Department of Dermatology, Division of Dermatopathology and Oral Pathology, Johns Hopkins University School of Medicine; Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center; Jeffrey P Callen, MD, Professor of Medicine, Chief, Division of Dermatology, University of Louisville School of Medicine; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Author and Editor Disclosure
Synonyms and related keywords:
hair follicle nevus, folliculo-sebaceous cystic hamartoma, trichofolliculoma, trichoma
Background
Folliculoma, also known as trichofolliculoma, is an asymptomatic, rare, benign tumor of the hair follicle, which is a hamartoma. Clinically, it appears as a small, solitary, skin-colored nodule on the face or scalp in adults. Often, a tuft of wool-like hair protrudes from a central pore.
Pathophysiology
Trichofolliculomas represent a hamartomatous, or organoid, adnexal tumor originating from the hair follicle. Immunohistochemical studies with cytokeratins reveal folliculomas differentiate mainly toward the hair bulge and the outer root sheath in the isthmus. All stages of follicular development can be observed in the lesion; the tumor is benign.
Frequency
United States
Folliculomas are uncommon. Given its benign nature, no large screening for this hair follicle tumor has been performed in the general population; therefore, an exact incidence has not been determined.
International
The condition has been reported worldwide. It is a rare entity with all nationalities.
Mortality/Morbidity
Folliculomas are benign asymptomatic lesions that may present as a cosmetic problem. Clinically, they are more likely to be confused with a more serious entity, ie, basal cell carcinoma; however, they have no malignant potential.
Race
A study performed with military personnel demonstrated that folliculomas are more common in whites than in any other race.
Sex
Folliculomas occur predominantly in males.
Age
- Although folliculomas represent a maldevelopment of the hair follicle unit, the lesions do not usually manifest until the late teens or possibly until the fourth decade of life. However, one report describes a congenital folliculoma on the cheek.
History
- Patients with this disorder note a small nodule on their face, or possibly scalp, ears, or neck. Although there is one report of multiple lesions, folliculomas normally present as solitary nodules.
- Lesions are asymptomatic and slow growing, with a diameter of 0.2-1 cm.
- Lesions have a central punctum through which the patient would note the presence of cottony hair extruding from the bump.
Physical
- Folliculomas are solitary tumors, most commonly found on the face or occasionally the scalp.
- The lesion is a firm, slightly elevated, pearly tumor with a central crater or punctum containing keratinous material or a wisp of wool-like or cottony hairs, usually white, protruding from it.
- If hairs protrude from the crater, the diagnosis is strongly suspected, as clinically, this is a highly diagnostic feature.
- Folliculomas have been identified in the vulva, albeit rarely.
- Also rarely, this condition has been associated with focal acantholytic dyskeratosis.
Causes
- Folliculomas are caused by a maldevelopment of the hair follicle unit.
- Lesions are organoid, or hamartomatous, adnexal tumors of hair follicle origin.
- They undergo anatomical changes corresponding to the regressing normal hair follicle in its various cycles.
Basal Cell Carcinoma
Dilated Pore of Winer
Milia
Molluscum Contagiosum
Nevi, Melanocytic
Syringoma
Trichoepithelioma
Other Problems to be Considered
Epidermal cyst
Pilar sheath acanthoma
Trichoadenoma
Lab Studies
- Once the diagnosis of folliculoma is established, either clinically or histologically, no laboratory workup is indicated.
Imaging Studies
- No imaging studies are indicated for this entity.
Histologic Findings
Folliculomas demonstrate a central pore leading to a large cavity in the dermis. The cavity reveals buds of hair roots on the sides and base of numerous well-formed sinuses. These maldeveloped hair follicle units possess a dermal papilla, a hair matrix, and the rudiments of root sheaths. Some of these hamartomatous hair units may form fine hair shaft structures, while others only produce keratinous fragments.
Pilomotor muscles and sebaceous glands are either not present or rudimentary in appearance. Some have described the sinus tracts as secondary follicles branching from the walls of the primary or main cavity. In the outer sheaths of these secondary follicles, large amounts of glycogen can be found. Additionally, these secondary epithelial proliferations may contain small keratinous cysts and vellus hair shafts.
Using antibodies to Ki67, proliferative Merkel cells have not been detected in folliculomas. Trichohyalin has been expressed in the secondary hair structures of folliculomas by antitrichohyalin antibody AE 15.
Medical Care
- Folliculomas are benign and require no specific therapy. However, for cosmetic purposes, or to ensure that the lesion is not a more serious entity, such as a basal cell carcinoma, a biopsy or removal is appropriate. Complete local excision is an adequate treatment for this entity.
- No medical treatment is available for folliculoma.
Surgical Care
- As stated above, complete primary excision is an adequate treatment for this lesion. If not totally removed, regrowth can occur.
- Folliculomas have been successfully treated with carbone dioxide and Er:YAG lasers.
Complications
- Folliculomas are not associated with complications, and cancerous tendencies have not been reported; they are completely benign growths.
Prognosis
- Prognosis of folliculomas is excellent because it has no sinister sequelae.
- Recurrence can occur if the lesion is not totally removed on excision.
Patient Education
- Patients need to know that these lesions are totally benign and require no follow-up care.
- Lesion may need to be excised to confirm diagnosis.
- There is a possibility of recurrence if lesion is not totally removed.
Medical/Legal Pitfalls
- Inasmuch as folliculomas are benign structures that are not premalignant, treatment is not legally required. Thus, the standard of care would include numerous therapies, including just watchful vigil of the skin lesion. Overzealous therapy with oral antimetabolites would not be acceptable.
- Bogle MA, Cohen PR, Tschen JA. Trichofolliculoma with incidental focal acantholytic dyskeratosis. South Med J. Aug 2004;97(8):773-5. [Medline].
- Gray HR, Helwig EB. Trichofolliculoma. Arch Dermatol. 1962;86:619-25.
- Hartschuh W, Schulz T. Immunohistochemical investigation of the different developmental stages of trichofolliculoma with special reference to the Merkel cell. Am J Dermatopathol. Feb 1999;21(1):8-15. [Medline].
- Ishii N, Kawaguchi H, Takahashi K, Nakajima H. A case of congenital trichofolliculoma. J Dermatol. Mar 1992;19(3):195-6. [Medline].
- Kurokawa I, Kusumoto K, Sensaki H, et al. Trichofolliculoma: case report with immunohistochemical study of cytokeratins. Br J Dermatol. Mar 2003;148(3):597-8. [Medline].
- Manabe M, Yaguchi H, Iqbal Butt K, et al. Trichohyalin expression in skin tumors: retrieval of trichohyalin antigenicity in tissues by microwave irradiation. Int J Dermatol. 1996;35:325-329. [Medline].
- Miescher G. Trichofolliculoma. Dermatologica. 1944;89:193-194.
- Mizutani H, Senga K, Ueda M. Trichofolliculoma of the upper lip: report of a case. Int J Oral Maxillofac Surg. Apr 1999;28(2):135-6. [Medline].
- Morton AD, Nelson CC, Headington JT, Elner VM. Recurrent trichofolliculoma of the upper eyelid margin. Ophthal Plast Reconstr Surg. Dec 1997;13(4):287-8. [Medline].
- Peterdy GA, Huettner PC, Rajaram V, Lind AC. Trichofolliculoma of the vulva associated with vulvar intraepithelial neoplasia: report of three cases and review of the literature. Int J Gynecol Pathol. Jul 2002;21(3):224-30. [Medline].
- Schulz T, Hartschuh W. Folliculo-sebaceous cystic hamartoma is a trichofolliculoma at its very late stage. J Cutan Pathol. Aug 1998;25(7):354-64. [Medline].
- Zimmermann T, Hartschuh W, Raulin C. [Facial folliculo-sebaceous cystic hamartoma. Treatment with CO2 and Er:YAG lasers]. Hautarzt. Mar 2004;55(3):289-91. [Medline].
Folliculoma excerpt Article Last Updated: Oct 5, 2006
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