A case of IgG4-related disease coexisted with rectal cancer

A 67-year-old man was referred to our hospital with suspicion of rectal tumor, hilar tumor, and urinary tumor. Colonoscopic findings were intermittent nodular lesions with redness which were atypical to primary rectal cancer. Endoscopic retrograde cholangiopancreatography showed narrowing of the bilateral intrahepatic bile duct. However, the findings were improved 1 month later. Blood biochemistry showed high level of serum IgG4 up to 1140 mg/dl. The patient matched to comprehensive diagnostic criteria for IgG4-related disease as a possible diagnostic case. Laparoscopic low anterior resection with creation of ileostomy was performed for rectal cancer. Histological findings revealed cancer cells spread horizontally at submucosal layer and subserosal layer. There was marked infiltration of the plasma cells and lymphocytes at tumor stroma, and more than half of the plasma cells were positive for IgG4. After surgery, the level of serum IgG4 was decreased to 597 mg/dl. Although the association with IgG4-related disease and colorectal disease is unclear, the tumor progression was atypical for rectal cancer. Some report that the disease may rise up the risk of a malignant disease. It is necessary to perform systemic examination keeping in mind for concurrence of malignancy.