Gastric Extramural Tumor Caused by Mycobacteria Infection With Immunoreconstitution Inflammatory Syndrome

Immunoreconstitution inflammatory syndrome (IRIS) was reported to occur in 7-13% of AIDS patients on anti-retroviral therapy (ART). IRIS due to Mycobacterium infection is one of the most difficult IRIS types to manage. A male patient in his early 70s was diagnosed with AIDS and treated with an ART. One year after starting ART, abdominal ultrasound was performed for screening and a 4 cm hypoechoic mass was found from the outside of the stomach to the surface of the hepatic lateral segment. Based on various imaging tests, including contrast CT, a malignant tumor, such as malignant lymphoma, was suspected. Then, a percutaneous tumor biopsy was performed. Pathologically, the tumor was recognized as mycobacterial granulomas. Disseminated mycobacterium avium complex can produce granulomas anywhere in the body. The patient was diagnosed with a mycobacterial infection associated with IRIS. When an intra-abdominal mass is found in a patient with HIV, both malignancy and mass formation due to opportunistic infections should be considered differential diseases.