Sir,
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.
Physical examination of the nodule in the upper lip region
Figure 2.
A central cavity with keratin in the dermis which is continuous with the surface epithelium (H and E, ×40)
Figure 3.
The cyst wall is lined by stratified squamous epithelium that has multiple tumor lobules (H and E, ×100)
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.
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REFERENCES
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