大腸癌との鑑別に苦慮した大腸原発悪性リンパ腫の1例

Primary Large Intestine Diffuse Large B-cell Lymphoma Similar to Type 2 Advanced Colorectal Cancer, Report of a Case

要旨　患者は67歳，男性．右李肋部痛を主訴に受診した．全大腸内視鏡検査を施行したところ，直腸に2型大腸癌様の病変，盲腸に粘膜下腫瘍様の隆起性病変を認め，進行直腸癌および盲腸転移性腫瘍を考えた．鑑別として悪性リンパ腫も否定できず両病変から生検を施行した．組織学的所見はともにびまん性大細胞型リンパ腫であった．CTでは腹部に多数のリンパ節腫脹を認めた．以上より腸管原発悪性リンパ腫，臨床病期Stage IIと診断しrituximab-CHOP療法を施行した．6コース終了後に病変はほぼ消失していた．

　A 67-year-old male, complaining of pain in the right upper abdomen, had a total colonoscopy after screening, and two protruded lesions were detected. The first lesion was found in the rectum, 30mm with depression, and the second one in the cecum, 25mm covered with normal mucosa. These endoscopic findings suggest rectal advanced carcinoma（type 2）and metastatic tumor. For definitive diagnosis, biopsy specimens were taken by endoscopy. The results revealed malignant lymphoma, diffuse large B-cell type（DLBCL）. CT images showed lymph node swelling around rectum, aorta and mesentery. The patient had chemotherapy using Rituximab-CHOP over a period of 6 courses. With treatment, the lymphoma entered complete remission.