An HIV-negative woman with chronic lymphopenia related to past sarcoidosis situated in the bone marrow presented with an inflammatory lesion in the iliac region due to a localized Mycobacterium genavense soft tissue infection. The lesion resolved after 12 months of antibiotic therapy with clarithromycin, ethambutol and ciprofloxacin. The patient had no recurrence of the subcutaneous abscess during a follow-up period of 14 months after the end of the treatment.