A Case of Trichoblastic Fibroma at the Cheek

Purpose: Trichoblastic fibroma originates from hair germ layer tumor which is a benign tumor mixture of epidermal and mesodermal factor. Trichoblastic fibroma was found only in adults and showed equal occurrence rate between men and women. Since it is a rare tumor, we report a case of a trichoblastic fibroma which developed on the right cheek. Methods: A 72 year-old male was treated with excisional operation 17 years ago due to a solitary tumor that developed on the same site. He returned to the hospital with an asymptomatic mass which have been increasing in size for the last 3 months. Results: In computerized tomography, a size of $2.7{\times}2.3{\times}0.8cm$ tumor was found in the subcutaneous tissue layer. Grossly, the mass was well-circumscribed, smooth-surfaced and flesh colored, and was lobulated and fragile. Pathologic observation showed diverse shaped and sized tumor cell nests and fibrocellular stroma consisting basophilic cells in dermal and subdermal layers. Immunohistopathologic staining showed positive reaction on pancytokeratin, CK-5/6, and bcl-2. Conclusion: By having no connection to the epidermis, and being positioned in the dermal and epidermal layers, typical pathologic findings make it possible to differentiate this tumor with basal cell carcinoma. This lesion is not clear whether it is a local recurrence or not, and it is necessary to observe a new recurrence in the future.

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