病理学的立場からみた前癌性疾患と癌との関係

RELATIONSHIP BETWEEN CARCINOMA AND PRECANCEROSIS:FROM THE PATHOLOGICAL ASPECT

　癌前駆性疾患と呼ばれるものは周知の如く，経験上長い経過中にしばしば癌化の傾向のある色々の病変の総称であつて決して特徴ある確立された疾患ではない。したがつてこれに含まれる疾患も広く，かつその性状や基源等は全く異なる諸種の病変にわたることは勿論である。皆見座長の解説にもあるように狭義のものは白色角化症，老人性角化腫，色素性乾皮症，広義のものは火傷，レ線皮膚炎，狼瘡などの慢性炎症の基地のあるもの等多数の病変が含まれる訳である。今回提示された症例は極めて広範な病変が包含されているが，これを通覧して癌前駆性疾患から癌化への過程における共通的変化がうかがえるかははなはだ疑問ではあるが，病理形態学的立揚から考察してみたいと思う。

　そこでこれら症例を大別すれば次の通りである。

Precancerous dermatoses are to be difined as a group of skin changes which may become to cancer in high frequency. They include (1) dermatoses with neoplastic nature. (2) genoder-matoses, and (3) chronic inflammatory dermatoses. They are not entities of diseases them-selves, but systems with latent potentiality of abnormal proliferation and development of tissue such as invasion or metastasis.

Process changing to cancer from these dermatoses shows various kinds of histopathologic pictures and is complicated as that of usual cancer is. However there are some common his-topathologic characteristics. These are as follows :

1) Irregularity in size, stainability and arrangement of the squamous and basal cells of the epidermis. Irregular wavy proliferation of spindleshaped cells.

2) Degeneration and dissociation of the basement membrane.

3) Connective tissue of the dermis shows the most important and characteristic changes in precancerous dermatoses. Proceeding the epithelial atypia, degeneration of collagen, distur-bance of lymphatic circulation, and changes of blood vessel which produce edema and cell infiltration in the dermis can be observed. These changes might become an internal carcinogenic stimulation and give some inpulse to neoplastic proliferation of the epithelial cell with poten-tiality and induce it to a cancer.