Abstract： HistopathologySolid-cystic hidradenoma (SCH) is located in the dermis and can be attached to the epidermis or extend into the subcutaneous tissue.The lesion is well circumscribed with clear edge.It can be encapsulated or unencapsulated.There were both a large cavity and a solid component in the tumor.The cyst is lined by flattened or cubic secretory cells,while the cystic wall is more often constituted by tumor cells.Therefore,the cystic cavity may be caused by the necrosis of tumor cell.The cysts consist of uniformly eosinophilic materials.The tumor cells were characteristic of slightly basophilic cytoplasm and round nuclei.Most SCH have a duct-like structure,which consists of a monolayer of cubical cells with eosinophilic walls (Fig.1A-1C).Tumor lobules are surrounded by collagen fibers,blood vessels,and other interstitium,which sometimes have transparent degeneration.1