Cutaneous Mycobacterium chelonae Infection During Ibrutinib Treatment in Chronic Lymphocytic Leukemia: A Case Report

Mycobacterium chelonae is a rapidly growing nontuberculous mycobacterium (NTM) that can infect both immunocompetent and immunocompromised hosts. Cutaneous and soft tissue infections are the most common manifestations and occur more frequently in individuals with underlying immune dysfunction. Patients with chronic lymphocytic leukemia (CLL), particularly those receiving targeted therapies such as ibrutinib, may be at increased risk of opportunistic infections. The diagnostic workup, microbiological findings, antimicrobial susceptibility testing, and therapeutic approach adopted for a cutaneous M. chelonae infection arising in a CLL patient four months after the introduction of ibrutinib were described. Clinical course and surgical management are also reported. A 60-year-old beekeeper with B-cell CLL developed a progressive cutaneous lesion on the left lower limb within four months of starting ibrutinib. Culture of a skin biopsy identified M. chelonae. Antimicrobial therapy was initiated based on in vitro susceptibility testing, resulting in partial clinical improvement. Complete resolution required surgical excision of the infected tissue followed by skin grafting. The patient's underlying hematologic disease, ongoing immunosuppression, and recent exposure to ibrutinib likely contributed to susceptibility and persistence of infection. This case highlights the increasing recognition of nontuberculous mycobacterial infections in immunocompromised individuals and underscores the importance of early diagnosis and susceptibility- guided therapy. Clinical response may be incomplete, and combined medical and surgical approaches may be required in selected cases. NTM infections should be considered in patients receiving Bruton's tyrosine kinase inhibitors who present with persistent, atypical, or non-healing cutaneous lesions. However, the association between ibrutinib therapy and susceptibility to infection remains uncertain, as multiple predisposing factors may coexist. Increased awareness of this possible association, together with careful clinical evaluation, may facilitate earlier diagnosis and improved management.