Colitis Cystica Profunda

Colitis Cystica Profunda

　Colitis cystica profundaは結腸または直腸の粘膜下層およびそれより深層に異所的に存在する粘液囊胞よりなる無茎ポリープ状の良性非腫瘍性病変であり，存在状況によって大腸の広い範囲に見られるびまん型（diffuse type）と，主として直腸に弧在性または少数個よりなる限局型（localized type）とに分けられる．腺上皮の異所的存在や粘液貯留のために粘液性腺癌との鑑別が問題となるが，本病変のなかには直腸の腺癌として取り扱われた症例が相当数あると考えられる．Goodall and Sinclair（1957）が本病変名を提唱して以来，今日までに57例の報告がなされているが，最近われわれは本症の1例を経験したので，その概略を紹介し，若干の文献的考察を加えながらその病理発生について検討した．

　Colitis cystica profunda is a non-neoplastic condition simulating an intramural tumor, and is characterized by the presence of mucus-containing cysts in the submucosa of the colon and rectum. We have gone through one case of this disease and discussed the pathogenesis on the basis of findings of 57 cases previously reported since Goodall and Sinclair (1957) proposed this entity.

　A 54-year-old male, who had undergone a fistulectomy in the anal region 33 years before the last admission, recently complained of anal bleeding at every defecation and underwent a radical operation of the rectum under the diagnosis of rectal carcinoma. The resected specimen showed grossly a solitary global elevation covered by innocent rectal mucosa, measuring 2.5 cm in diameter. It was situated in the left rectal wall just above the dentate line. The lesion was limited to the submucosa and composed of many dilated mucous cysts lined by mucus-secreting epithelium without atypicality, partially presenting colonic mucosal structures.

　As to the pathogenesis of this lesion many authors have believed that the cysts originate from inflammatory lesions, although a few have thought that the localized type of this lesion was due to a congenital malformation of colonic mucous glands. The findings of our case suggest that downward growth of the epithelium through defect or weakness of the muscularis mucosae following inflammation be responsible. The supporting findings are the colonic glands, covered by thin muscularis mucosae, dipping into the submucosa and the epithelium of mucous cysts communicating through narrow channels with the rectal mucosa, associated with the non-specific inflammation.

　We must be aware of this lesion in order to avoid confusion with a mucus-producing adenocarcinoma at the time of biopsy.