Psoas Abscess Due to Mycobacterium avium in A Patient with Chronic Lymphocytic Leukemia－Case Report and Review

Abstract

Infections may constitute a serious complication in patients with chronic lymphocytic leukemia (CLL). New treatment agents including obinutuzumab and ibrutinib have improved the progression-free survival in CLL, and data suggest a similar overall infection risk and a limited risk of opportunistic infections when compared to standard chemo-immunotherapy. Nevertheless, cases of opportunistic infections including non-tuberculous mycobacterial (NTM) in CLL patients have recently been published. We present a case of a 74-year old man with extensive prior CLL treatment history, including most recently obinutuzumab. He developed an abscess of the psoas muscle and inguinal lymphadenopathy. An inguinal node biopsy specimen showed infection with Mycobacterium avium, confirmed by broad-spectrum mycobacterial PCR, M. avium-specific PCR, and mycobacterial culture. This case and our literature review suggest that physicians should be aware of opportunistic infections in patients with CLL. Diagnostic differentiation from CLL disease progression, Richter's transformation to aggressive lymphoma, and secondary malignancy relies on histological and appropriate microbiological studies from biopsy material of affected organs. Infection prophylaxis in CLL should be considered, including vaccinations and intravenous immune globulin replacement.

Keywords: Mycobacterium avium; abscess; chronic lymphocytic leukemia; ibrutinib; immunosuppression; infection; non-tuberculous mycobacteria; obinutuzumab.

Figure 1

Mycobacterium avium psoas abscess and inguinal lymphadenitis in a patient with chronic lymphocytic leukemia (CLL). (A) Computed tomography with intravenous and oral contrast, done at the time of initiation of intravenous immune globulin (IVIG) replacement, demonstrates normal and symmetric psoas muscle appearance (arrowhead), without abscess formation. (B) Large, septated abscess (dashed arrows) located within the right psoas muscle (arrowhead), of which biopsy material grew M. avium in culture. (C) One month later, notable reduction in psoas abscess volume (arrowhead) after introduction of computed tomography (CT)-guided percutaneous pigtail catheter drain (arrow). (D) CT scout image corresponding to axial image C, demonstrating the course of the percutaneous pigtail catheter drain (arrow).