Trichogerminoma: a case report / 中华皮肤科杂志

ABSTRACT

A case of benign follicular neoplasm-trichogerminoma-is reported.A 48-year-old man presented with a 10-year history of asymptomatic subcutaneous nodule in the chest.Histological examination revealed a well-circumscribed lesion composed of variously sized lobuli and cysts in the deep dermis and separated from the surrounding tissue by a fibrous capsule.Most lobuli consisted of concentrically arranged clear cells in the central area and basophilic cells in a palisade arrangement in the peripheral area.The tumor cells displayed a multi-directional differentiation toward hair bulb,inner root sheath,outer root sheath and infundibulum of hair follicles.Immunohistochemically,the tumor cells expressed AE1/AE3,CK5/6 and CK17,but were negative for CK20 or CK7.There was a sharp contrast in immunohistochemical findings between the central clear cells and peripheral basophilic cells.Based on the histological and immunohistochemical features,a diagnosis of trichogerminoma was made.