title: Suppurative inflammation with microabscess and pseudocyst formation is a characteristic histologic manifestation of cutaneous infections with rapid-growing Mycobacterium species.
abstract: Mycobacterial infections of the skin classically cause a granulomatous tissue reaction. We have observed a suppurative pattern of inflammation associated with infections by rapid-growing Mycobacterium species in immunocompromised patients. We report 6 cases in skin and soft tissue with an unusual but consistent lack of a predominance of granulomatous inflammation. Of the 6 cases, 4 had predominantly (approximately 75%) suppurative inflammation, 1 case predominantly demonstrated (approximately 75%) a mix of acute and chronic inflammation, and 1 case showed an approximately equal contribution of suppurative and granulomatous inflammation. All 6 cases showed abscess formation and numerous acid-fast bacilli (AFB) on AFB stain and were confirmed by tissue culture. Of these 6 cases, 2 had microabscesses with central pseudocysts harboring microorganisms. Five patients were taking oral prednisone, and 1 had an uncharacterized immunodeficiency. These cases highlight the need for awareness of this unusual manifestation of infection with rapid-growing Mycobacterium species, particularly in immunocompromised patients.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Gable
authors.forename: Derek K
authors.initials: DK
authors.lastname: Marsee
authors.forename: Dan A
authors.initials: DA
authors.lastname: Milner
authors.forename: Scott R
authors.initials: SR
authors.lastname: Granter
mesh_terms: D000038:Abscess / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000009:adverse effects; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D007153:Immunologic Deficiency Syndromes / Q000150:complications / Q000276:immunology; D007249:Inflammation / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009164:Mycobacterium Infections / Q000276:immunology* / Q000473:pathology; D011241:Prednisone / Q000009:adverse effects; D017192:Skin Diseases, Bacterial / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D013492:Suppuration / Q000276:immunology / Q000382:microbiology / Q000473:pathology
chemical_list: D000893:Anti-Inflammatory Agents; D011241:Prednisone