Rice bodies in nontuberculous mycobacterial tenosynovitis of the wrist joint

Nontuberculous mycobacterial (NTM) tenosynovitis is a rare extrapulmonary infection that presents as a painless, slow-growing mass and often evades timely diagnosis due to nonspecific symptoms. We report the case of an 89-year-old female farmer who developed a recurrent mass in her right forearm. Despite two prior excisions, the lesion recurred, prompting further investigation. Magnetic resonance imaging revealed low-intensity areas, and intraoperative findings included rice bodies. Histopathology showed an epithelioid granuloma, while the anti-GPL-core IgA antibody test was negative.Mycobacterium intracellulare, a species within the Mycobacterium avium complex (MAC), was identified by culture from the excised tissue, confirming the diagnosis. Treatment with antituberculous agents was administered, and no recurrence was observed at one-year follow-up. This case underscores the importance of integrating imaging, intraoperative findings, and microbiological testing in the diagnosis of NTM tenosynovitis.