Orbital lipogranulomatous inflammation harboring Mycobacterium abscessus

Purpose: A case of iatrogenic Mycobacterium abscessus orbital infection is presented to call attention to its distinct histopathologic appearance, mec hanism of organism, virulence. and clinical management. Methods: Clinicopathologic analysis of an orbital infection caused by M. ab scessus is described. Detailed histologic analysis is performed to provide insight into the mechanism of infection and correlate the features of the o rbital infection with that of atypical mycobacteriosis at other body sites. Results: A 71-year-old woman had an orbital mass in the supranasal orbit af ter a blepharoplasty. T e mass consisted of a dimorphic inflammatory reacti on with a superficial purulent reaction and a deeper granulomatous process consisting of epithelioid tubercles, each centered about a lipid vacuole. A cid-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 desmo plastic reaction. Microbiologic culture studies identified M. abscessus. A combination of surgical intervention and antibiotic therapy for 4 weeks eli minated the infection. Conclusions: Acid-fast stains should be performed on any orbital lesion sho wing an apparent lipogranulomatous reaction. Although clinical management o f orbital atypical microbacteriosis is difficult, the combination of surgic al and specific antimicrobial intervention is effective. Our study contribu tes to an evolving understanding of the mechanism of human infectivity of t hese low-virulence organisms by suggesting that the orbital fat is a source of lipid material that can harbor the organisms, allowing them to escape h ost immunosurveillance.