Author divides the hair follicle carcinoma clinicopathologically into two subtypes, that is the epidermal tumor and the dermo-subdermal tumor. The former group consists of malignant trichilemmoma (MT) and trichilemmomal carcinoma (TCa) in order of malignant potency, whose precursor or prototype is trichilemmoma. The latter group consists of proliferating trichilemmal cyst (PTC) and malignant proliferating trichilemmal tumor (MPTT), whose precursor or prototype is trichilemmel cyst. According to this classification, the principal mode of surgical treatment of hair follicle carcinoma is concluded theoretically. Carcinoma in situ (MT, PTC) could be safely managed with conservative excision but invasive carcinoma should be excised more widely and deeply with lymphnode dissection, if necessary. Besides, dermosubdermal tumors must be handled more carefully and radically than epidermal tumors, because of their deep location and metastasizing capability.
