抄録
A 65-year-old Japanese female presented our clinic with a painful eruption on the lips and the oral mucosa. She had first noticed an asymptomatic whitish plaque on the buccal mucosa, several years before which had gradually increased in size and elevated. The lesion was composed of two parts. One was a hyperkeratotic, well-circumscribed, whitish elastic hard califlower-like tumor. The other was a slightly elevated whitish patches on the buccal mucosa adjacent to the tumor. The histopathological examination of the tumor revealed that the epidermis was markedlyhyperkeratotic and hypertrophic, extending into the deep dermis. The epidermis wascomposed of the pale-staining large cells, and showed a moderate loss of polarity. Mitotic figures and pleomorphism were rarely found. The histopathological examination of the white patches of the buccal mucosa showed hyperkeratosis and acanthosis. Many cells on the epidermis were large, which were similar to those of the tumor. We considered that the tumor was oral florid papillomatosis developed from the white patches which was diagnosed leukoplakia.
