Abstract: The early clinical manifestations of patients with Mycobacterium marinum infection are not typical, which is easy to be misdiagnosed and missed diagnosed. This paper reports a case of a patient with a 2-year history, who did not receive timely diagnosis and treatment, resulting in gradual aggravation of skin lesions and a huge deep ulcer in the late stage with ligament involvement. The ulcer healed after 6 months of doxycycline combined with clarithromycin treatment.

Key words: Mycobacterium marinum infection, enormous ulcer