|Year : 2014 | Volume
| Issue : 4 | Page : 185-186
An unusual location of a pilar sheath acanthoma
Jeffrey Albert Kushner1, Richard Scott Thomas2, Russell John Young2
1 Department of Internal Medicine, Largo Medical Center, Largo, FL, USA
2 Department of Dermatology, Silver Falls Dermatology, Salem, OR, USA
|Date of Web Publication||14-Oct-2014|
Jeffrey Albert Kushner
500 Belcher Road S Apartment 161, Largo, FL 33771
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Pilar sheath acanthoma is a rare, benign follicular hamartoma that frequently presents as an asymptomatic, flesh-colored papule with a central opening. First described in 1978 by Mehregan and Brownstein, these lesions generally appear on the upper lip of elderly patients. We present an interesting case of a pilar sheath acanthoma presenting on the earlobe in a middle-aged male. To the best of our knowledge, this is the first reported case of a pilar sheath acanthoma found in such a unique location.
Keywords: Pilar sheath acanthoma, benign follicular hamartoma, pilar neoplasm
|How to cite this article:|
Kushner JA, Thomas RS, Young RJ. An unusual location of a pilar sheath acanthoma. Int J Trichol 2014;6:185-6
| Introduction|| |
Pilar sheath acanthoma is a rare, benign follicular hamartoma. They frequently present as an asymptomatic, flesh-colored papule with a central opening typically appearing on the upper lip of elderly patients.  We present an interesting case of a pilar sheath acanthoma on the earlobe in a middle-aged male. To our knowledge, this is the first reported case of a pilar sheath acanthoma found in such a unique location.
| Case report|| |
The case we present here is about a 63-year-old Caucasian male presented to our office complaining of a bump in his right earlobe for several years. He reported the ability to express contents out of the bump frequently, but denied any previous trauma to the area, including ear piercings, or any previous treatment. In addition, he reported a benign past medical history.
Physical exam revealed a 4 mm skin colored nodule with a small central opening located on his right earlobe [Figure 1]. Provisional diagnoses included: epidermal inclusion cyst, dilated pore of Winer, and a trichofolliculoma.
|Figure 1: Physical exam revealed a 4 mm skin colored nodule with central opening located in the right earlobe|
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A 4 mm punch biopsy was performed and sent for routine H and E staining, which revealed bulbous aggregations of isthmic epithelial cells containing sebaceous ducts emanating from a dilated infundibulum and extending into the dermis, consistent with a pilar sheath acanthoma [Figure 2]. In addition to being diagnostic, the biopsy was also curative, and no further treatment was required.
|Figure 2: (a-c) Histopathology showed skin with bulbous aggregations of isthmic epithelial cells containing sebaceous ducts emanating from a dilated infundibulum and extending into the dermis (×4, ×10, ×20 magnification)|
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| Discussion|| |
A pilar sheath acanthoma is a rare, benign neoplasm typically affecting the face of middle-aged and elderly patients.  Physical exam typically reveals a solitary skin-colored papule or nodule, 5-10 mm in diameter with a central pore-like opening plugged with keratin. Usually, these lesions are almost exclusively found on the upper lip, although they can be found anywhere on the head and neck. Case reports have documented lesions in other locations such as the nasolabial fold,  cheek,  forehead,  and postauricular area.  The differential diagnosis includes epidermal inclusion cyst, dilated pore of Winer, and a trichofolliculoma. A shave or excisional biopsy of the lesion in question helps confirm the diagnosis.
Pilar sheath acanthoma is histopathologically characterized by a central, cystically dilated follicle containing keratinous material that opens to the surface.  Buds of squamous epithelium radiate from the central pore. Tumor lobules comprised of outer rooth sheath epithelium extend into adjacent dermis and possibly into the subcutis.  Infundibular keratinization of the epithelium, as well as individual tumor cells containing abundant glycogen, are possible findings.
Microscopically, pilar sheath acanthoma must be distinguished from a dilated pore of Winer and trichofolliculoma. A dilated pore of Winer contains larger cystic spaces surrounded by radiating thin strands or finger-like projections of epithelium that extend into the dermis and surrounding connective tissue. This is in contrast to the thicker, more lobular arrangement found in a pilar sheath acanthoma.  A trichofolliculoma contains many secondary hair follicles radiating from the wall of the primary follicle as well as the outer and inner root sheath. In addition, there is a well-formed stroma, which is absent in pilar sheath acanthoma.  These lesions also contain trichohyaline granules within the secondary follicles.
There are no reported associations of pilar sheath acanthoma with other systemic manifestations as the pathology is strictly cutaneous. Since these lesions are benign neoplasms, they do not necessitate further treatment once the diagnosis has been determined. If the patient opts to remove these lesions for cosmetic reasons, potential options include surgical excision or electrodesiccation and curettage.
| Conclusion|| |
Pilar sheath acanthoma is a rare, benign neoplasm of middle age and elderly patients. Historically, these lesions are found almost exclusively on the upper lip although isolated cases have been reported on the forehead, cheek and postauricular area. Our patient appears to be the first documented case of a pilar sheath acanthoma presenting on an earlobe. It is, therefore, important for dermatologists to consider a diagnosis of pilar sheath acanthoma beyond the classically described locations.
| References|| |
|1.||Mehregan AH, Brownstein MH. Pilar sheath acanthoma. Arch Dermatol 1978;114:1495-7. |
|2.||Bavikar RR, Gaopande V, Deshmukh SD. Postauricular pilar sheath acanthoma. Int J Trichology 2011;3:39-40. |
|3.||Vakilzadeh F. Pilar sheath acanthoma. Hautarzt 1987;38:40-2. |
|4.||Choi YS, Park SH, Bang D. Pilar sheath acanthoma - report of a case with review of the literature. Yonsei Med J 1989;30:392-5. |
|5.||Smolle J, Kerl H. Pilar sheath acanthoma-A benign follicular hamartoma. Dermatologica 1983;167:335-8. |
|6.||Weedon D. Tumors of cutaneous appendages. Weedon's Skin Pathology. 3 rd ed., Ch. 33. Philadelphia, PA: Churchill Livingstone; 2010. p. 765-6. |
|7.||Elston DM, Ferringer T. Pilar and sebaceous neoplasms. Dermatopathology. 2 nd ed., Ch. 4. Philadelphia, PA: Elsevier-Saunders; 2014. p. 80. |
[Figure 1], [Figure 2]