Long S A, Hurt M A, Santa Cruz D J
Department of Pathology, St. John's Mercy Medical Center, St. Louis, Missouri 63141-8221.
J Cutan Pathol. 1988 Dec;15(6):353-8. doi: 10.1111/j.1600-0560.1988.tb00564.x.
We report 6 cases of an immature variant of trichoepithelioma which histologically appears to show differentiation toward the primitive hair germ. The lesions presented in mature adults (mean age 44 years). Four occurred in men and 2 in women. Four lesions occurred on extremities, an unusual location for trichoepitheliomas. Histologically, the lesions were characterized by well-circumscribed, but unencapsulated, dermal collections of small tumor lobules composed of basaloid cells with invaginations resembling primitive dermal hair papillae. There was no adenoidal growth pattern or horn cyst formation. The separation of the immature lesions from those of classical trichoepithelioma and basal cell carcinoma can be made if multiple morphological features are considered; no one particular finding is diagnostic. The major differential features between the immature trichoepithelioma and basal cell carcinoma are circumscription, tumor lobule uniformity, occasional immature hair germs, and lack of retraction artifact of the tumor lobules from the stroma. The differential features between the immature and classical trichoepithelioma are less conspicuous. The immature form typically exhibits no horn cysts, displays fewer primitive hair structures, and lacks the adenoidal growth patterns of the tumor lobules which are usually present in the classical trichoepitheliomas.
我们报告了6例毛发上皮瘤的未成熟变体病例，其组织学表现为向原始毛胚分化。病变出现在成年人（平均年龄44岁）中。4例发生在男性，2例发生在女性。4个病变发生在四肢，这对于毛发上皮瘤来说是不寻常的部位。组织学上，病变的特征是边界清楚但无包膜，真皮内有由基底样细胞组成的小肿瘤小叶聚集，伴有类似原始真皮毛乳头的内陷。没有腺样生长模式或角囊肿形成。如果考虑多种形态学特征，可将未成熟病变与经典毛发上皮瘤和基底细胞癌的病变区分开来；没有一个特定的发现具有诊断意义。未成熟毛发上皮瘤与基底细胞癌之间的主要鉴别特征是边界、肿瘤小叶均匀性、偶尔出现的未成熟毛胚以及肿瘤小叶与间质之间缺乏退缩假象。未成熟型与经典毛发上皮瘤之间的鉴别特征不太明显。未成熟型通常不表现角囊肿，原始毛发结构较少，且缺乏经典毛发上皮瘤中通常存在的肿瘤小叶腺样生长模式。
