老人性角化症，皮角，有棘細胞癌および脂漏性角化症の合併せる1例

CONCOMITANCE OF SENILE KERATOSIS, CUTANEOUS HORN, SQUAMOUS CELL CANCER AND SEBORRHEIC KERATOSIS

I．はじめに

　老人性角化症は，1869年Neumannが初めて記載し，以後Dubreuilh^1），Freudenthal^2）により脂漏性角化症から分離独立された希なる疾患で，癌前駆症（precancerous dermatosis）の1つと考えられている。本症をLever^3）は1/2度の有棘細胞癌であるとし，その悪性化は20〜25％に達するという。一方皮角の多くは，その組織像より老人性角化症の増殖型の中に含有されている。

　以上のごとく，老人性角化症は皮角，有棘細胞癌と密接な関係があり，一方脂漏性角化症との鑑別も必ずしも容易ではない。

Concomitant presence of senile keratosis, cutaneous horn, squamous cell cancer and seborrheic keratosis is reported in a 76-year-old Japanese farmer. Ten years ago, he noticed dark brownish macules and dry, hard crusts on the scalp, face and earlobes. Since one year, they have gradually increased in number and size, and some of them developed to be hyperkeratotic tumors and a reddish tumor. The scalp was atrophic in appearance on the first consultation. Multiple brownish macules with scales and keratotic plaques were grouped on the scalp and face. A dark brownish, horny tumor of less than 1.5cm. in diameter was seen in the parietooccipital region and on the left earlobe and left upper lip. There was a half-spherical, sessile reddish tumor with crusts on the frontooccipital portion. Microscopic studies of the scalp lesions with serial sections revealed definite changes of senile keratosis into squamous cell cancer. In addition, multiple tumors of seborrheic keratosis in an adenoid type were also scattered among the lesions, especially in the adjacent areas of senile keratosis. These findings suggest a possibility that some lesions of seborrheic keratosis might become those of senile keratosis. Out of the three cutaneous horns, one on the upper lip was seborrheic keratosis, while the remainders were senile keratosis. Twelve cases of senile keratosis, so far reported in Japan, were reviewed and discussed.