Abstract: A 59-year-old female presented with right thumb nodule for more than 2 months. Before the onset, her right thumb was stabbed by shrimp. Histopathology examination revealed infectious granuloma. Mycobacterium qPCR (tissue) was positive, and ultrasound was consistent with flexor tendon tenosynovitis of the right finger. The diagnosis of tenosynovitis caused by infection with Mycobacterium marinum was made. Her condition improved obviously after treated with compound clindamycin and minocycline hydrochloride.

Key words: Mycobacterium marinum, tenosynovitis, deep infection