1、典型皮损为孤立、无蒂、肤色到红色的结节。

2、发病部位很广泛，头、颈、胸、腹、肢体的近端和手均可发生。

3、组织起源：末端汗管的外层细胞和真皮上部的小汗腺导管。

4、组织学特征：肿瘤细胞替代表皮并向真皮广泛增生，形态单一的小立方形汗孔瘤细胞与周围相邻上皮的角质形成细胞界限清楚，瘤细胞间可见细胞间桥，周边细胞核不呈栅栏状排列，可见明显的胞浆内空腔；肿瘤由纤维血管间质支持；偶见色素沉着。

 【● Cords and nests of small keratinocytes attached to the epidermis
           ● Nests are sharply delimited from adjacent epidermis
           ● Also ducts and sharply delimited islands of squamous epithelium
           ● Either intraepidermal (“hidroacanthoma simplex”), intradermal (“dermal duct tumor”)   or mixed (most common)
          ● Dermis has reactive vessels and inflammatory infiltrate
          ● Also heavily pigmented variants】
     5、鉴别诊断：

● Basal cell carcinoma
      ● Seborrheic keratosis
      ● Acrosyringeal adenomatosis
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