Miura George, Maeda Takuya, Ujiie Hideyuki
Department of Dermatology, Faculty of Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
J Dermatol. 2025 Apr;52(4):730-734. doi: 10.1111/1346-8138.17610. Epub 2025 Jan 8.
Trichogerminoma (TG) is a rare, benign, cutaneous adnexal tumor originating from the hair germ epithelium. It typically presents as an asymptomatic, slowly enlarging nodule predominantly on the head, face, or trunk. Despite its benign nature, precise diagnosis is crucial because of its potential to become malignant. There has been no previous report on the dermoscopic findings of TG. In this study, we reviewed the dermoscopic findings of two cases in detail and contrasted them with the pathological findings. In the first case, an 80-year-old male presented with a forehead nodule that was initially suspected to be basal cell carcinoma (BCC). Dermoscopic examination revealed arborizing vessels, milia-like cysts, and comedo-like openings. Histological examination supported a diagnosis of TG, showing basaloid cell nests with peripheral palisading and pathognomonic "cell balls." The second case involved a 50-year-old female with a nodular lesion on her scalp. Dermoscopy showed arborizing vessels, milia-like cysts, and blue-gray ovoid nests. Based on the presence of "cell balls" observed in histopathological examination, this case was also diagnosed as TG. This report is seminal in documenting the specific dermoscopic patterns associated with TG, notably the presence of arborizing vessels in conjunction with features indicative of adnexal differentiation, such as milia-like cysts and comedo-like openings. Although differentiating TG from other follicular tumors such as BCC and trichoblastoma based solely on dermoscopy is challenging, these features suggest follicular differentiation in TG. This report contributes uniquely to the existing data on TG, enhancing our understanding of this rare tumor and how to diagnose it.
毛发胚芽瘤（TG）是一种罕见的良性皮肤附属器肿瘤，起源于毛胚芽上皮。它通常表现为无症状、缓慢增大的结节，主要位于头部、面部或躯干。尽管其本质为良性，但由于其有恶变的可能，精确诊断至关重要。此前尚无关于毛发胚芽瘤皮肤镜表现的报道。在本研究中，我们详细回顾了2例毛发胚芽瘤的皮肤镜表现，并将其与病理结果进行对比。第一例，一名80岁男性，前额出现一个结节，最初怀疑为基底细胞癌（BCC）。皮肤镜检查发现树枝状血管、粟丘疹样囊肿和粉刺样开口。组织学检查支持毛发胚芽瘤的诊断，显示基底样细胞巢伴有周边栅栏状排列及特征性的“细胞球”。第二例，一名50岁女性，头皮有一个结节性病变。皮肤镜显示树枝状血管、粟丘疹样囊肿和蓝灰色卵圆形巢。基于组织病理学检查中观察到“细胞球”，该病例也被诊断为毛发胚芽瘤。本报告首次记录了与毛发胚芽瘤相关的特定皮肤镜模式，特别是树枝状血管与提示附属器分化的特征（如粟丘疹样囊肿和粉刺样开口）同时存在。虽然仅通过皮肤镜将毛发胚芽瘤与其他毛囊肿瘤（如基底细胞癌和毛母细胞瘤）区分开来具有挑战性，但这些特征提示毛发胚芽瘤存在毛囊分化。本报告为现有的毛发胚芽瘤数据做出了独特贡献，增进了我们对这种罕见肿瘤及其诊断方法的理解。
