J Drugs Dermatol. 2021 Dec 1;20(12):1346-1348. doi: 10.36849/jdd.5978.
Trichilemmal cysts (TCs) are the most common cystic lesions arising on the scalp and up to 2% give rise to a proliferating trichilemmal tumor (PTT). A rare subset of PTTs are termed malignant due to their histologic characteristics, aggressive behavior and potential for metastasis. The histological hallmark of TCs and PTTs is the absence of a granular layer resulting in abrupt trichilemmal keritanization.
毛囊角化性外根鞘瘤（trichilemmal cysts，TCs）是头皮最常见的囊性病变，其中约 2%可发展为增殖性毛囊角化性外根鞘瘤（proliferating trichilemmal tumor，PTT）。由于组织学特征、侵袭性行为和转移潜能，PTT 的罕见亚型被称为恶性。TCs 和 PTT 的组织学特征是缺乏颗粒层，导致突然的外根鞘角化。
