家族性大腸腺腫症の経過観察におけるポリープの形態学的変化

orphologic Alterations of Polyps during a Long-term Follow-up Study of Non-operated Familial Adenomatosis Coli

要旨　初回検査で癌の合併がないと判断して長期間follow-upを行った家族性大腸腺腫症5例について形態学的変化を考察した．家族性大腸腺腫症においては，ポリープの密度が長期間変化しない静止期があり，その後に密度が高くなる変動期のあることが推測された．一方，ポリープの大きさは変化する傾向にあり，その静止期は密度の静止期に比して短いものと考えられた．著明な増大傾向を呈する病変については，大腸隆起性病変の診断理論に基づき，大きさに形の要素を加えて分析することにより癌化の可能性を判定できた．しかしながら，癌化した病変をすべて検査所見上（X線・内視鏡所見）に把握することは困難であり，長期間のfollow-upは極めて危険なものであることが示された．

　A long-term follow-up study by x-ray and endoscopy was done to the patients with familial adenomatosis coli (FAC) who refused surgery in the first examination by x-ray or endoscopy. Morphologic alterations of polyps had been observed in five cases for more than seven years (the shortest seven years and one month, and the longest eleven years and nine months).

　Density of polyps did not change during the observation periods in four cases (p＞0.1), and it became higher in about seven years in one case (p＜0.01). It was suggested that there is a static phase of the density of polyps for a long time in FAC, which is followed by a changing phase. On the other hand, size of polyps increased gradually in five cases (p＜0.001). It was suggested that there is also a static phase of the size of polyps, which may be shorter than that of the density of polyps.

　There were several polyps which showed a marked increasing tendency of size, but they did not always develop into cancer. Two lesions developed into advanced cancers in one case, and one of them could not be detected until surgery. One lesion developed into cancer with submucosal involvement in one case. Some lesions remained pedunculated, though their size was over 4 cm. Not only size but also form of the lesions should be considered for the differential diagnosis of adenoma and cancer.

　It is hazardous to attempt follow-up study of FAC. Doctors' efforts should be directed to persuading the patients with FAC to accept early surgery.