Inflammatory Myofibroblastic Tumor of the Retroperitoneum Including Chronic Granulomatous Inflammation Suggesting Tuberculosis: A Case Report.

An inflammatory myofibroblastic tumor (IMT) is a solid tumor of unknown etiology frequently affecting children and young adults and commonly affecting the lung or orbital region. We present a case involving a 41-year-old man who had an IMT combined with Mycobacterium tuberculosis infection in the retroperitoneum. He presented with only pain in the right lower abdomen without accompanying symptoms; a retroperitoneal mass was found on computed tomography. The tumor had invaded the end of the ileum and was attached to the omentum, so mass excision could not be performed. The tumor was completely excised surgically and had histological features diagnostic of an IMT. Histologic findings of the omentum were positive for Ziehl-Nielsen staining for acid-fast bacilli and for a positive polymerase chain reaction for M. tuberculosis. The patient had no apparent immune disorder. These findings made this case exceptional because IMTs, which are mostly due to atypical mycobacteria, have been found mainly in immunocompromised patients.