Calcium oxalate crystal deposition in necrotizing otomycosis caused by Aspergillus niger.

Numerous calcium oxalate crystals were present within fruiting heads of Aspergillus niger and among necrotic debris in a case of bilateral invasive otomycosis occurring in a diabetic female with end stage renal disease. This is the first report of in vivo calcium oxalate crystal deposition associated with Aspergillus niger at this anatomic site. The presence of localized oxalate crystals within necrotic tissue from the external auditory canal is presumptive of otomycosis caused by Aspergillus niger, and may serve as a diagnostic clue to the etiologic agent before histologic demonstration of hyphae or growth in culture.