殿部に発生した悪性増殖性外毛根鞘腫の1例皮膚悪性腫瘍;;悪性増殖性外毛根鞘腫;;毛包癌

摘要

We report a case of malignant proliferating trichilemmal cyst of a 63-year-old man that was located on the left buttock for 20 years. The lesion had rapidly enlarged in the previous one month. A tumor measuring 11.5 X 2.2 X 4.5cm was removed with wide excision. The cyst wall consisted of basaloid cells, clear cells, and keratotic material with trichilemmal kera-tinization. Based on these histopathologic findings of the tumor, this case was diagnosed as a proliferating trichilemmal cyst. Two years and seven months after the excision, there is no evidence of local recurrence or metastasis. To the best of our knowledge, only eight cases of such a tumor occurring in this location have been reported from Japan.