Mycobacterium immunogenum-Induced Thrombocytopenia

Mycobacterium immunogenum is a fast-growing non-tuberculous mycobacterium often found in soil, water, and aerosols. It primarily affects immunocompromised individuals. One common area of infection is the pulmonary system, but lymph nodes, bones, and joints are also commonly involved. We report a case of a young female with a two-year history of lymphadenopathy who developed thrombocytopenia with petechiae, bruising, and mucosal bleeding. Initially, she had a positron emission tomography/computed tomography (PET/CT) scan showing elevated standardized uptake value concerning for malignancy, but a biopsy shortly after revealed more of a reactive follicular hyperplastic etiology. Her platelet count was severely low (3 K/uL) and a diagnosis of immune (idiopathic) thrombocytopenic purpura (ITP) was made. After numerous negative tests, a Karius test was performed for possible infectious etiology, which revealed Mycobacterium immunogenum. The patient responded well to intravenous immunoglobulin and was managed outpatient without complications.  This case highlights the rare association of Mycobacterium immunogenum with ITP. There are studies that relate the occurrence of ITP in patients with Mycobacterium tuberculosis, another bacterium of similar taxonomy to Mycobacterium immunogenum. This case report is significant because there is limited research on the complications of Mycobacterium immunogenum, particularly its relationship to ITP. Given the lack of information regarding this association, this report serves as a catalyst for further research into identifying potential rare causes of ITP.