Sleater J, Beers B, Stefan M, Kilpatrick T, Hendricks J
Department of Pathology, University of Florida College of Medicine, Gainesville 32610.
Am J Dermatopathol. 1993 Oct;15(5):423-8.
Proliferating trichilemmal cyst (PTC) is an uncommon tumor that usually arises on the scalp of elderly women. Its biologic nature is that of a benign lesion with occasional local recurrences. PTC can be confused both grossly and microscopically with squamous cell carcinoma and malignant PTC. Distinction between these lesions has historically been made on a histologic basis. We present four cases of PTC. Histologically, the lesions consisted of lobules of basaloid cells admixed with larger pale-staining cells with abrupt trichilemmal type of keratinization and peripheral palisading embedded in a fibrous stroma. Flow cytometry performed on nuclear extracts of the lesions revealed two of the four lesions to have nondiploid DNA content. Proliferation index, measured by immunohistochemical staining with Ki-67 monoclonal antibody along with mitotic rate count, was higher in the two nondiploid lesions as compared with their diploid counterparts. The results raise the question of the significance of aneuploidy and increased proliferation indices in otherwise benign PTC.
增殖性外毛根鞘囊肿（PTC）是一种罕见的肿瘤，通常发生于老年女性的头皮。其生物学性质为良性病变，偶有局部复发。PTC在大体和显微镜下都可能与鳞状细胞癌及恶性PTC相混淆。以往对这些病变的鉴别是基于组织学。我们报告4例PTC。组织学上，病变由基底样细胞小叶组成，混有较大的淡染细胞，有突然的外毛根鞘型角化，周边呈栅栏状排列，包埋于纤维性间质中。对病变细胞核提取物进行的流式细胞术检测显示，4例病变中有2例DNA含量为非二倍体。通过Ki-67单克隆抗体免疫组化染色及有丝分裂率计数测得的增殖指数，在2例非二倍体病变中高于其二倍体对应病变。这些结果提出了非整倍体及增殖指数增加在其他方面为良性的PTC中的意义问题。
