Orbital lipogranulomatous inflammation harboring Mycobacterium abscessus

A case of iatrogenic Mycobacterium abscessus orbital infection is presented to call attention to its distinct histopathologic appearance, mechanism of organism, virulence, and clinical management.

Clinicopathologic analysis of an orbital infection caused by M. abscessus is described. Detailed histologic analysis is performed to provide insight into the mechanism of infection and correlate the features of the orbital infection with that of atypical mycobacteriosis at other body sites.

A 71-year-old woman had an orbital mass in the supranasal orbit after a blepharoplasty. The mass consisted of a dimorphic inflammatory reaction with a superficial purulent reaction and a deeper granulomatous process consisting of epithelioid tubercles, each centered about a lipid vacuole. Acid-fast bacilli were found in the lipid vacuoles but not elsewhere in the specimen. Each tubercle was surrounded by a zone of lymphocytes and a desmoplastic reaction. Microbiologic culture studies identified M. abscessus. A combination of surgical intervention and antibiotic therapy for 4 weeks eliminated the infection.

Acid-fast stains should be performed on any orbital lesion showing an apparent lipogranulomatous reaction. Although clinical management of orbital atypical microbacteriosis is difficult, the combination of surgical and specific antimicrobial intervention is effective. Our study contributes to an evolving understanding of the mechanism of human infectivity of these low-virulence organisms by suggesting that the orbital fat is a source of lipid material that can harbor the organisms, allowing them to escape host immunosurveillance.