Mandibular Nodule Caused by Mycobacterium marinum with False Positive Interferon-γ Release Assay.

Mycobacterium marinum is a ubiquitous organism inhabiting both fresh and salt water. It can cause human diseases such as skin and soft tissue infection. The organism is also known to cause a false positive reaction to interferon-γ release assay, the test to diagnose latent tuberculosis infection. Here, we present a case of submandibular nodule caused by M. marinum with positive T-SPOT®.TB test, which was likely to be false positive.