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AUTHOR AND EDITOR INFORMATION

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Author: Michael S Howard, MD, Consulting Staff, Georgia Dermatopathology Associates

Coauthor(s): Bruce R Smoller, MD, Chief of Dermatopathology, Professor, Departments of Dermatology and Pathology, University of Arkansas Medical Center

Editors: James W Patterson, MD, Director of Dermatopathology, Professor of Pathology and Dermatology, Departments of Pathology and Dermatology, University of Virginia Medical Center; Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA; Rosalie Elenitsas, MD, Associate Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System; Joel M Gelfand, MD, MSCE, Medical Director, Clinical Studies Unit, Assistant Professor, Department of Dermatology, Associate Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center

Author and Editor Disclosure

Synonyms and related keywords: hamartoma of hair follicle tissue, hair follicle tumor

INTRODUCTION

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Background

Trichofolliculoma represents an uncommon hamartoma of hair follicle tissue, typically occurring on the face of adults (see Image 8). The prognosis is excellent, and therapy is usually directed toward cosmetic improvement.

Pathophysiology

Although the precise etiology of trichofolliculoma is uncertain, these tumors are not associated with systemic disease or other skin disorders. Trichofolliculomas are believed to represent abortive differentiation of pluripotent skin cells toward hair follicles.

Frequency

International

Trichofolliculoma represents an uncommon clinical entity.

Mortality/Morbidity

Trichofolliculomas are associated with minimal clinical morbidity; no confirmed cases of malignant transformation or clinical mortality are reported in the literature.

Race

In reported cases, trichofolliculomas demonstrate no definitive racial predilection.

Sex

No definitive sexual predilection is observed in reported cases, although sporadic reports indicate a probable male preponderance.

Age

From published reports, trichofolliculoma appears to primarily be a tumor of adults; however, at least 1 case of congenital trichofolliculoma has been reported.


CLINICAL

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History

Patients typically present with a single, flesh-colored or whitish nodule or papule of varying duration, typically on the face (most frequently around the nose).

Physical

  • Classic trichofolliculomas have a central pore or black dot, possibly draining a sebaceouslike material.
  • A tuft of white hair may be present emerging from the central pore.

Causes

  • Usually, these tumors develop spontaneously.
  • Rarely, a prior history of trauma at the tumor site is obtained.


DIFFERENTIALS

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Basal Cell Carcinoma
Dilated Pore of Winer
Epidermal Inclusion Cyst
Trichoepithelioma

Other Problems to be Considered

Dermal nevus
Fibrofolliculoma
Folliculosebaceous hamartoma


WORKUP

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Histologic Findings

Following surgical excision, these tumors are found to consist of a dilated primary follicle lined by infundibular, stratified squamous epithelium and opening to the skin surface.

From the central follicle outward, numerous secondary and tertiary follicles can be observed, presenting at various levels of hair-follicle differentiation. Hair structures may be observed within the hair follicle lumen; small sebaceous elements may be found within the follicular units.

Minimal lymphocytic or granulomatous inflammation may be present. An abundant connective tissue stroma is also present surrounding the follicular structures.

Abundant Merkel cells have been demonstrated within the follicular epithelium, supporting the concept that trichofolliculomas are hamartomas.

A variant of the trichofolliculoma is the sebaceous trichofolliculoma, featuring similar histologic features, except for the presence of numerous well-differentiated sebaceous lobules emptying into the central, dilated primary follicle. Sebaceous trichofolliculoma demonstrates histologic overlap with folliculosebaceous cystic hamartoma. Some consider the latter tumor to be a sebaceous trichofolliculoma in telogen phase. A single case of trichofolliculoma with perineural invasion has been reported in the literature.


TREATMENT

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Surgical Care

Simple surgical excision is typically curative.


FOLLOW-UP

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Prognosis

  • The prognosis is excellent. Although reports exist of recurrence at the primary site, these events are rare.


MULTIMEDIA

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Media file 1:  Low-power view of trichofolliculoma with a primary follicle opening onto the skin surface.
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Media type:  Photo

Media file 2:  Edge of the primary follicle with associated secondary and tertiary budding follicular structures.
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Media type:  Photo

Media file 3:  Higher magnification of budding follicular structures.
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Media type:  Photo

Media file 4:  Low-power view of a section of trichofolliculoma demonstrating budding follicular structures and associated stroma.
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Media type:  Photo

Media file 5:  Higher magnification of budding follicular structures and associated stroma.
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Media type:  Photo

Media file 6:  Low-power view of sebaceous trichofolliculoma demonstrating dilated, primary follicle; budding follicular structures; and numerous associated sebaceous lobules.
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Media type:  Photo

Media file 7:  Higher magnification of central primary follicle and associated sebaceous lobules.
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Media type:  Photo

Media file 8:  Clinical appearance of trichofolliculoma.
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Media type:  Photo


REFERENCES

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  • Gray HR, Helwig EB. Trichofolliculoma. Arch Dermatol. 1962;86:99-105.
  • 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].
  • Headington JT. Tumors of hair follicle differentiation. In: Farmer E, Hood A, eds. Pathology of the Skin. 1990:596-614.
  • Ishii N, Kawaguchi H, Takahashi K, Nakajima H. A case of congenital trichofolliculoma. J Dermatol. Mar 1992;19(3):195-6. [Medline].
  • Kligman AM, Pinkus H. The histogenesis of nevoid tumors of the skin. The folliculoma--a hair-follicle tumor. Arch Dermatol. Jun 1960;81:922-30. [Medline].
  • McKee P. Pathology of the Skin. 2nd ed. 1996:15.25-15.28.
  • Pinkus H, Sutton RL. Trichofolliculoma. Arch Dermatol. Jan 1965;91:46-9. [Medline].
  • Plewig G. Sebaceous trichofolliculoma. J Cutan Pathol. Dec 1980;7(6):394-403. [Medline].
  • Stern JB, Stout DA. Trichofolliculoma showing perineural invasion. Trichofolliculocarcinoma?. Arch Dermatol. Aug 1979;115(8):1003-4. [Medline].
  • Tanimura S, Arita K, Iwao F, et al. Two cases of folliculosebaceous cystic hamartoma. Clin Exp Dermatol. Jan 2006;31(1):68-70. [Medline].
  • Wick MR, Swanson PE, Barnhill RL. Sebaceous and pilar tumors. In: Barnhill R, ed. Textbook of Dermatopathology. 1998:593-621.

Trichofolliculoma excerpt

Article Last Updated: Feb 22, 2007