Mycobacterium avium Complex Infection-Related Immune Reconstitution Inflammatory Syndrome Mimicking Lymphoma in an Human Immunodeficiency Virus-Infected Patient

Abstract

In acquired immunodeficiency syndrome (AIDS) patients, immune reconstitution inflammatory syndrome (IRIS) due to Mycobacterium avium complex (MAC) infection is one of the most difficult IRIS types to manage. We report an unusual case of MAC-associated IRIS. At first the patient was diagnosed human immunodeficiency virus (HIV) infection after he was admitted with pneumocystis pneumonia. After starting antiretroviral therapy he presented unmasked IRIS with MAC infection. Next, he was hospitalized with continuous loose stools and new-onset fever. Investigation included computed tomography (CT), which showed homogeneous enhancement and enlargement of the lymph nodes (LN), elevation of ferritin (>1,650 ng/mL) and lactate dehydrogenase (306 IU/L) levels, and F- fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) scan, which showed increased FDG uptake. These findings were highly indicative of lymphoma. We performed laparoscopic biopsy of the mesenteric LN, and the biopsy culture grew MAC. So we made a diagnosis of MAC-associated. Therefore, IRIS must be considered as a possible diagnosis when AIDS patients develop new symptoms or exhibit exacerbations of existing symptoms. Furthermore the biopsies should be conducted.

Keywords: Acquired immunodeficiency syndrome; Lymphoma; Mycobacterium avium complex.

Figure 1. The series of CD4 cell count and HIV RNA PCR level. The arrows indicate the date of important medication or procedure were conducted.

HIV, human immunodeficiency virus; RNA, ribonucleic acid; PCR, polymerase chain reaction; NTM, non-tuberculous mycobacterium; ABC, abacavir; 3TC, lamivudine; RAL, raltegravir; TDF, tenofovir disproxil; FTC, emtricitabine; LN, lymph node; EVG, elvitegravir.

Figure 2. Abdomen/pelvic computed tomography axial plane shows multiple borderline size lymph nodes, paraaortic, aortocaval, retrocaval, and mesentery (red arrows).(Sixteen days after starting HAART).

HAART, highly active antiretroviral therapy.

Figure 3. Bone marrow biopsy specimen revealed positive staining for acid fast bacilli.ositive (black arrows). (Ziehl-Neelsen stain, x 400).

Figure 4. (A) Abdomen/pelvic computed tomography axial plane shows multiple lymph nodes enlargement along mesentery (red arrows, Thirty four days of starting anti-MAC chemotherapy); (B) Abdomen/pelvic computed tomography shows multiple lymph nodes enlargement along mesentery (red arrows).

MAC, Mycobacterium avium complex.

Figure 5. (A) Positron emission tomography image shows multiple enlarged hypermetabolic LNs in mesentery and retroperitoneum of abdomen, right retrocrural area (maximum standard uptake value = 13.4), right lower paratracheal, subcarinal and right hilar area and diffuse hypermetabolic activity in spleen and bone marrow (red arrows); (B) positron emission tomography/computed tomography image.

Figure 6. After 10 months of first visit, follow up abdomen/pelvic computed tomography shows slightly decreased size, but still remained multiple enlarged lymph nodes along mesentery (red arrows).