Topical application of an antibiotic can result in myospherulosis.


Features of myospherulosis:

(1) The patient has a history of application of a topical antibiotic within a petrolatum base, typically following surgery.

(2) The patient develop swelling, pain and/or drainage at the site.

(3) A biopsy shows a fibroinflammatory response and foreign body granulomatous reaction with cystlike spaces that contain yeast-like brownish spherules. The spherules are derived from transformed erythrocytes.


Sites where reported include:

(1) paranasal sinus

(2) oral or dental surgery

(3) bone

(4) soft tissue


Diagnosis involves exclusion of fungus by:

(1) negative fungal culture

(2) negative GMS stain for fungus

Rarely both myospherulosis and a fungal infection can coexist.


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