International Journal of Trichology

: 2015  |  Volume : 7  |  Issue : 4  |  Page : 187--188

Pilar sheath acanthoma presenting as a nevus

Tumay Ozgur1, Metin Temel2,  
1 Department of Pathology, Reconstructive and Aesthetic Surgery, School of Medicine, Mustafa Kemal University, Serinyol Hatay, Turkey
2 Department of Plastic, Reconstructive and Aesthetic Surgery, School of Medicine, Mustafa Kemal University, Serinyol Hatay, Turkey

Correspondence Address:
Tumay Ozgur
Department of Pathology, School of Medicine, Mustafa Kemal University, Serinyol-Hatay

How to cite this article:
Ozgur T, Temel M. Pilar sheath acanthoma presenting as a nevus.Int J Trichol 2015;7:187-188

How to cite this URL:
Ozgur T, Temel M. Pilar sheath acanthoma presenting as a nevus. Int J Trichol [serial online] 2015 [cited 2023 Jan 30 ];7:187-188
Available from:

Full Text


Pilar sheath acanthoma (PSA) is a rare benign follicular neoplasm, which was first described by Mehregan and Brownstein in 1978. [1] PSA usually presents as an asymptomatic, flesh colored papule with a central opening localized at the lower lip with exceptional presentations such as ear lobe, postauricular region, or cheek. [1],[2],[3]

A 42-year-old female referred with a solitary, slow-growing nodular lesion at the upper lip region for 6 months. Physical exam revealed a 4 mm, pink-brown colored nodule with a central opening [Figure 1]. Under clinical prediagnosis of melanocytic nevus, an excisional biopsy was performed. In a microscopic examination, a cystic cavity that communicated with surface epidermis has been observed. The wall of the cystic cavity was composed of solid tumor islands extending in the deep dermis [Figure 2]. The cavity was lined with stratified squamous epithelium filled with keratin [Figure 3].{Figure 1}{Figure 2}{Figure 3}

PSA is an uncommon, benign follicular tumor occurring in the faces of middle-aged and elderly patients. These lesions can present at any location such as cheek, ear lobe on the head, and neck. In our case, a 42-year-old female was presented with a pink-brown colored nodular lesion opening at the upper lip region. The differential diagnosis includes trichofolliculoma and dilated pore of Winer.

Trichofolliculomas contain many seconder hair follicles radiating from the wall of the primary follicle with outer and inner root sheaths in a well-formed stroma which are absent in PSA. Dilated pore of Winer has a central cavity and an acanthotic cystic wall with finger-like branching; besides these PSA do not show the hair shafts and sebaceous glands and does not have a fibrovascular stroma. Keratoacanthoma should also be kept in mind when PSA is in consideration because of its clinic similarity. PSA do not regressed in contrast to keratoacanthoma. [1],[2],[3],[4]

PSA is a cutaneous neoplasm and does not have any relationship with other systemic pathologies. There are no other additional treatment modalities because of its benign nature. The lesion is usually excised with cosmetic reasons but in our case, the patient defines the slow enlargement of the mass probably due to keratinisation that resulted with excision. [2] Therefore, dermatologists and plastic surgeons should consider benign follicular infundibulum tumors at the nodular lesions with a pore located on the face beside a melanocytic lesion.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Mehregan AH, Brownstein MH. Pilar sheath acanthoma. Arch Dermatol 1978;114:1495-7.
2Kushner JA, Thomas RS, Young RJ. An unusual location of a pilar sheath acanthoma. Int J Trichology 2014;6:185-6.
3Bavikar RR, Gaopande V, Deshmukh SD. Postauricular pilar sheath acanthoma. Int J Trichology 2011;3:39-40.
4Weedon D. Tumors of cutaneous appendages. Weedon's Skin Pathology. 3 rd ed., Ch. 33. Philadelphia, PA: Churchill Livingstone; 2010. p. 765-6.