Mycobacterium avium Complex Presenting as Inferior Rectus Pyomyositis

Non-tuberculous mycobacterium is a prevalent pathogen that—despite myriad systemic presentations, particularly among immunocompromised hosts—rarely presents in the periocular and adnexal region. The authors present here the first reported case of pyomyositis caused by Mycobacterium avium complex in an immunocompetent patient presenting with progressive, insidious proptosis, found to have a “cold abscess” in the inferior rectus warranting surgical drainage and prolonged medical treatment. In addition to its novelty, this case reviews pyomyositis of the extraocular muscles and NTM infections in the periocular and adnexal region. This case underscores that non-tuberculous mycobacterium infections can affect immunocompetent individuals, despite their typical association with immunocompromised states. Moreover, pyomyositis—although rarely caused by non-tuberculous mycobacterium—can also occur in immunocompetent patients. Ultimately, these patients require surveillance by both ophthalmologists and infectious disease specialists to ensure complete eradication of this fastidious organism.