Brownstein M H, Arluk D J
Cancer. 1981 Sep 1;48(5):1207-14. doi: 10.1002/1097-0142(19810901)48:5<1207::aid-cncr2820480526>3.0.co;2-1.
Comparison of 50 proliferating trichilemmal cysts with 50 "ordinary" trichilemmal cysts indicated that both types almost invariably occurred on the scalps of women, were diagnosed clinically as cysts, followed a benign course, and featured trichilemmal keratinization. A spectrum was observed from trichilemmal cyst with minimal hyperplasia, to full-blown proliferating trichilemmal cyst. Occasionally, patients had ordinary trichilemmal cysts on their scalps associated with a proliferating trichilemmal cyst. In addition to trichilemmal keratinization, which is characteristic of the follicular isthmus, proliferating trichilemmal cysts showed a wider range of differentiation, including features of the follicular infundibulum, the lower nonkeratinizing portion of the follicular outer root sheath, and sebaceous cells. Intense inflammatory infiltrate and cellular atypia, sometimes of significant proportions, were also seen in proliferating trichilemmal cysts. It is concluded that trauma and inflammation may induce a trichilemmal cyst to proliferate and show a broader spectrum of pilosebaceous differentiation and cellular atypia of pseudocarcinomatous proportions, while maintaining its benign biologic behavior.
50个增殖性外毛根鞘囊肿与50个“普通”外毛根鞘囊肿的比较表明，这两种类型几乎都发生在女性头皮上，临床上被诊断为囊肿，病程呈良性，且具有外毛根鞘角化特征。观察到一个范围，从增生极少的外毛根鞘囊肿到完全成熟的增殖性外毛根鞘囊肿。偶尔，患者头皮上既有普通外毛根鞘囊肿又伴有增殖性外毛根鞘囊肿。除了具有毛囊峡部特征的外毛根鞘角化外，增殖性外毛根鞘囊肿还表现出更广泛的分化，包括毛囊漏斗部、毛囊外根鞘下部非角化部分以及皮脂腺细胞的特征。在增殖性外毛根鞘囊肿中还可见强烈的炎症浸润和细胞异型性，有时比例显著。得出的结论是，创伤和炎症可能诱导外毛根鞘囊肿增殖，并表现出更广泛的毛囊皮脂腺分化和假癌样比例的细胞异型性，同时保持其良性生物学行为。
