Trichoadenoma of the upper lip.

Background: Trichoadenoma of Nikolowski, who describe the first cases in 1958, is a rare and benign tumor of the hair follicle. It is well-differentiated and slowly-growing. The clinical appearance of Trichoadenoma (TA) can be similar to basal cell carcinoma or epidermal cyst.
Results: We describe a 44-year-old male who was referred for nodular lesion on the upper lip and a TA was diagnosed. Oral examination showed exophytic yellow mass located between mucous membrane of the upper lip and vestibular gingiva, 1.2 per 0.8 cm. Anamnestic data was non-contributory. An excisional biopsy of the lesion was performed. Microscopically, the lesion consisted of multiple keratinous cysts lined with stratified squamous epithelium and intermingled with solid islands of basaloid cells lying within sclerotic stroma. The pathological diagnosis was TA. The surgical wound healed uneventfully.
Conclusion: Because the lesion is unique, it is uncertain how aggressive or indolent the tumor might be. Therefore, the microscopical analysis is mandatory. At the best of our knowledge, this is the second case of trichoadenoma of the lip.