家族性大腸腺腫症(FAP)は,常染色体優性遺伝疾患であり,若年から高率に大腸癌を発症するとともに,特徴的な大腸外病変を来たす.FAP家系のサーベイランスと予防的大腸切除術の普及により,大腸癌罹患率は減少し,死因に占める大腸癌の割合も減少してきている.反面,FAP患者の生存期間の延長とともに,大腸外病変の重要性が増加してきた.本稿では,デスモイド腫瘍に代表される腸管外病変について概説した.デスモイド腫瘍は,FAP患者の死因の第二位を占め,FAP患者の約10%に発症する.病因としては遺伝子的要因,手術,性ホルモンの関与が報告されている.腹壁のデスモイド腫瘍には切除術が第一選択とされるが,腹腔内のデスモイド腫瘍に対しては切除術よりも保存的治療が優先される.他の腸管外病変として,甲状腺腫瘍,網膜色素上皮肥大(CHRPE),肝芽腫,脳腫瘍などを取り上げ,若干の知見を紹介した.
Familial adenomatous polyposis (FAP) is an autosomal, dominantly inherited disease predisposing to colon cancer. Surveillance of the pedigree and widespread use of prophylactic colectomy have resulted in a reduction in the incidence of colon cancer in FAP patients. Thus, a greater percentage of morbidity in FAP patients appears to be attributable to extracolonic manifestation of the disease. In this article, the characteristics of extra-intestinal manifestation, as represented by desmoid tumors, are reviewed. Desmoid disease is a second cause of death in FAP patients, and it is associated in approximately ten percent of cases. Trauma, sex steroids, and an inherited defect have been implicated in the etiology of desmoids. Surgery is accepted as the first-line treatment for abdominal wall desmoids, while intraabdominal desmoids should be treated medi-cally. We also reviewed extra-intestinal manifestations, such as thyroid tumors, congenital hypertrophy of retinal pigment epithelium (CHRPE), hepatoblastomas, and brain tumors.