Published online Jan 21, 2017. doi: 10.3748/wjg.v23.i3.551
Peer-review started: September 17, 2016
First decision: November 9, 2016
Revised: December 5, 2016
Accepted: December 16, 2016
Article in press: December 19, 2016
Published online: January 21, 2017
Processing time: 118 Days and 16.9 Hours
Mucosa-associated lymphoid tissue (MALT) lymphoma usually originates from the stomach and presents with low 18F-fluorodeoxyglucose (FDG) avidity with average maximum standard uptake value of 3.6. Colorectal MALT lymphoma is a rare entity that contributes to 1.6% of all MALT lymphomas and < 0.2% of large intestinal malignancies. The case reported herein firstly revealed stage IIE MALT lymphoma with unexpected higher 18F-FDG avidity of 18.9 arising at the colorectal anastomosis in a patient with a surgical history for sigmoid adenocarcinoma, which was strongly suspected as local recurrence before histopathological and immunohistochemical examinations. After accurate diagnosis, the patient received four cycles of standard R-CVP regimen (rituximab, cyclophosphamide, vincristine and prednisone), combined target therapy and chemotherapy, instead of radiotherapy recommended by National Comprehensive Cancer Network guidelines. He tolerated the treatment well and reached complete remission.
Core tip: This case highlighted the possibility of development of metachronous neoplasms at the colorectal anastomosis, especially rare mucosa-associated lymphoid tissue (MALT) lymphoma with unusual 18F-fluorodeoxyglucose (FDG) hypermetabolism. Chromosomal translocation leading to the activation of nuclear factor-κB pathway in proliferative B cells stimulated by pathogens may explain the etiopathogenesis for MALT lymphoma. Despite being indolent, MALT lymphoma can be successfully imaged by 18F-FDG-positron emission tomography (PET)/computed tomography (CT), and shows great 18F-FDG avidity. This indicates that PET/CT can be added to the workup of MALT lymphoma. Considering that MALT lymphoma originates from many organs, patient-tailored treatment including radiotherapy, chemotherapy and immunotherapy is necessary.