Splenic Abscess Caused by Mycobacterium avium Complex

A 51-year-old man with a history of AIDS (CD4 count of 59 cells/µL), anemia, neutropenia, and AIDS-related dementia presented with persistent fever, abdominal pain, and diarrhea of 2 months' duration. He did not adhere to his regimen of HAART and prophylactic therapy with atovaquone and azithromycin.

The patient was severely cachectic and febrile (temperature, 39.4ºC [103ºF]). He had moderate diffuse abdominal tenderness, hepatomegaly (liver span, 17 cm), and massive nontender splenomegaly. White blood cell count was 2.8/µL, with 57% neutrophils; hemoglobin level, 6.4 g/dL; and platelet count, 317,000/µL. Findings on a chest radiograph were normal.

Fadi I. Jabr, MD, of Florence, Ore, reports that a CT scan of the abdomen revealed hepatomegaly with no focal lesions and splenomegaly with 3 hypodense, well-circumscribed masses. The CT slice here shows the largest mass (2.1 3 3.2 3 2 cm).

Examination of a specimen obtained byCT-guided fine-needle aspiration of the splenic lesion revealed clusters of acid-fast bacilli. These were later identified as Mycobacterium avium complex (MAC).

Disseminated MAC infection occurs in up to 16% of patients with AIDS and is associated with anemia, fever, diarrhea, and weight loss.¹ It can involve the blood, lymph nodes, spleen, and liver. Occasionally, MAC infection can cause bulky abdominal lymphadenopathy and hepato- splenomegaly.^2,3 On microscopic examination, the spleen and liver may exhibit granuloma.⁴ However, splenic MAC abscesses, such as occurred in this patient, are very rare.

This patient was treated with oral rifabutin, azithromycin, and ethambutol. His condition continued to deteriorate, however, and he died after a month and a half of treatment.