直腸癌経過中に発症したCronkhite-Canada症候群の1例

Cronkhite-Canada Syndrome Encountered During the Course of Rectal Cancer, Report of a Case

要旨　患者は75歳男性で，入院17か月前に下血が出現し直腸癌の診断を受けたが放置していた．10か月後下痢が出現し，その後皮膚色素沈着に気付いた．14か月間に10kgの体重減少を認め1981年8月入院した．入院時，手，足の爪の萎縮を認め，直腸に全周性の限局潰瘍型腫瘤を触知した．その後体毛の脱落を認めた．検査成績では軽度の貧血と血清K，Ca値の低下，血清総蛋白の著明な低下（4.3g/dl）を認め，CEAは12.4ng/dlと高値を示した．消化管X線および内視鏡所見では胃，結腸，直腸に多数のポリープがみられたが，食道，小腸にはみられなかった．直腸には全周性の狭窄を示す限局潰瘍型腫瘍を認めた．生検では胃ポリープはhyperplastic polypであり，直腸腫瘍は腺癌であった．直腸癌の治療目的にて直腸切断術を施行した．切除標本では直腸に6.0×4.7cmの限局潰瘍型癌を認め，標本全体に無数の小ポリープを伴う横ひだがみられた．組織学的には直腸腫瘍は高分化型腺癌であった．ポリープには2つの型がみられ，大部分を占める型は腺管の囊胞状拡張，間質の浮腫，炎症細胞浸潤がみられ，他の型のポリープは腺腫または腺腫性腺管の集簇である．術後，下痢の消失，体毛の再生，皮膚色素沈着の改善がみられ，手足の爪は剥離し再生した．人工肛門粘膜面のポリープは背が低くなり，発赤は軽度となりoozingは消失した．その後肺炎に罹患し，下痢，粘血便の再発がみられ肺炎のため死亡した．下血発症後1年8か月であった．

　A 75-year-old man was diagnosed as having rectal cancer because of bloody stool developed 17 months before hospitalization but he took no account of any treatment. Diarrhea developed 10 months later on and skin pigmentation was subsequently noticed. He had lost about 10 kg in weight in the preceding 14 months and was then hospitalized in August 1981. At the time of hospitalization, atrophied finger-and toe-nails were noted and a localized ulcerating tumor was palpated in the rectum. After hospitalization, loss of hair developed. Laboratory investigation revealed mild anemia, hypocalcemia, hypopotassemia and hypoproteinemia (TP 4.3g/dl). CEA showed a higher value of 12.4ng/ml. Roentgenographic and endoscopic examinations showed numerous polyps in the stomach, colon and rectum, but no polyps were demonstrated in the esophagus and small intestine. Localized ulcerating tumor showing an extended stenosis was observed in the rectum. Biopsy revealed these gastric polyps as hyperplastic and the rectal tumor of adenocarcinoma. Rectectomy was performed for treating rectal cancer. Surgical specimen showed a localized ulcerating tumor sized 6.0×4.7 cm and transverse plica with numerous small polyps. Histologically, the rectal cancer was of well differentiated adenocarcinoma. There were two types of polyp, a major type having cystic dilation of the gland, stromal edema and inflammatory cell infiltration and another minor type showing adenoma or aggregate of adenomatous glands.

　After the operation, diarrhea, alopecia, hyperpigmentation and nail atrophy gradually improved. Polyps on the mucous membrane of artificial anus became lower; redness became less severe and oozing disappeared. However, pneumonia occurred thereafter, followed by recurrence of diarrhea and mucous bloody stool. He ultimately died of pneumonia, one year and eight months after the onset of bloody stool. No definite conclusion is still available concerning the malignant change of polyps in Cronkhite-Canada syndrome.

　Twelve cases of this syndrome associated with cancer are discussed. Consequently, it could suggest that this type of cancer did not result from the malignant change of polyps of Cronkhite-Canada syndrome but this syndrome accidentally occurred in patients with cancer.