Abstract: 【Abstract】 Objective To explore the clinical and pathological characteristics of solitary fibrofolliculoma. Method The clinical data of 15 patients with single fibrofolliculoma diagnosed by histopathology at Gulou Hospital in Nanjing from April 2008 to December 2023 were reviewed. Clinical information, pathological features, immunohistochemistry, and follow?up information were collected. Result Among the 15 cases, there were 9 males and 6 females; The rash is mostly manifested as single yellow or white papules or nodules with a diameter of 0.2 - 1.2 cm; The affected areas include the nose （8 cases）, ears （4 cases）, eyes （2 cases）, and occipital region （1 case）. Histopathology: A reticular and lobulated structure is formed within the dermis layer, centered around well?developed hair follicles. Cells generally have no obvious anisotropy, and some may show proliferation of hair sheaths. 7 routine immunohistochemical staining examinations: tumor epithelial cells were diffusely positive for p63 and p40, and smooth muscle actin （SMA） was positive, S100、 Localized positive for epithelial cell membrane antigen （EMA） and negative for carcinoembryonic antigen （CEA）; Tumor mesenchymal cells are CD10 positive, CD34 focal positive, SMA and desmin negative. All patients underwent surgical resection of the tumor and were followed up for 4 - 192 months postoperatively, with no recurrence observed. Conclusion Single fibrofolliculoma typically presents as a papule or nodule, most commonly occurring on the head, neck, and face. Immunohistochemically, the mesenchymal cells surrounding the tumor tissue are positive for CD10, whereas those within the tumor do not express CD10, which is helpful for its diagnosis.

Key words: Hamartoma, Fibrofolliculoma, Single, Organizational pathology, Immunohistochemistry