A Pedunculated Follicular Hamartoma: A Case Showing a Central Trichofolliculoma‐like Tumor with Multiple Trichogenic Tumors

The document reported a rare case of a pedunculated follicular hamartoma on the nasal septum of a 77-year-old Japanese male. The nodule measured 11x11x10 mm and was skin-to-pink colored. Histopathological examination revealed a well-formed dilated hair follicle at the tumor's central pore, containing keratin debris and vellus hairs. Epithelial cells proliferated from the central follicle to the peripheral epidermis, forming long thin strands or immature follicle-like structures. A primary germinal bud with thick concentric collagen fibers and sparse elastic fibers was a distinctive feature. Although the tumor showed characteristics of a trichofolliculoma with desmoplasia, trichogenic trichoblastomas, and perifollicular fibromas, it was more accurately described as a pedunculated follicular hamartoma due to its pathological and clinical features.