Rhinoscleroma is a chronic infection caused by the organism Klebsiella rhinoscleromatis that most often involves the nasal cavity, but also can involve the upper airways, in young to middle aged adults. It initially appears similar to a common cold, but then a granulomatous destructive and disfiguring process ensues with resultant airway obstruction. The end stage is extensive fibrosis with scarring. Seen here is the florid granulomatous stage, with extensive chronic inflammation with numerous plasma cells, lymphocytes, and characteristic large clear to vacuolated Mikulicz cells (macrophages) beneath the squamous mucosa at the left.

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