CASE DESCRIPTION
A 69-year-old man was admitted with intermittent fever (maximum of 39ºC), weight loss of 10 Kg, anorexia and malaise in the previous month. He denied any respiratory, genitourinary or gastrointestinal symptoms. He had a medical history of superficial urothelial carcinoma of the bladder treated with transurethral resection (TUR) followed by intravesical BCG instillations every 6 weeks, completed 1 year earlier, with no evidence of cancer recurrence.
Upon admission, he was febrile (auricular temperature of 38ºC) but the rest of his physical examination was normal.
Laboratory blood tests showed progressive pancytopenia (nadir values: hemoglobin of 8.3 g/dL, 1950 leukocytes, 74000 platelets); hepatic cholestasis (alkaline phosphatase of 286 UI/L, gamma-glutamyl transpeptidase of 514 UI/L); lactate dehydrogenase of 249 UI/L and C-reactive protein of 44.7 mg/L. Repeated blood and urine cultures were sterile. M. tuberculosis DNA in urine was negative. Serological tests for HIV, cytomegalovirus, epstein-barr, hepatitis B and C, bartonellosis, brucellosis, Q fever were also negative as was a rheumatological antibody panel. A thoraco-abdomino-pelvic CT scan only revealed hepatosplenomegaly. An echocardiogram showed no vegetations. A bone marrow biopsy was performed and revealed non-caseating granulomas (Figure 1) with negative acid-fast bacillus (AFB) and fungal stains. TheMycobacterium tuberculosis complex PCR was negative. Despite a negative PCR and a pending AFB culture, the medical team made a presumptive diagnosis of disseminated BCG infection considering the history of intravesical BCG therapy and the histological findings in the bone marrow. The patient started on isoniazid 300mg id, rifampin 600mg id and ethambutol 1200mg id with clinical and analytical improvement, and was discharged one week later. After 45 days of incubation, the AFB culture from the bone marrow aspiration grew Mycobacterium bovisthus confirming the clinical diagnosis. The patient presented full recovery after 12 months therapy.