Image Gallery: Normal vs Abnormal Ear Cytology

Elizabeth R. May, DVM, DACVD, University of Tennessee

ArticleLast Updated June 20161 min readPeer ReviewedWeb-Exclusive
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Ear cytology provides an abundance of useful clinical information that can easily be obtained with in-house testing. When combined with otoscopic examination findings, cytology is an efficient tool in helping clinicians make a diagnosis and assess treatment response (ie, whether to discontinue or change therapy). Cytology samples should be examined under low power magnification (100×) to identify cell types and high power magnification (1000×) to identify infectious organisms, especially bacteria.

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Figure 1

Keratinocyte with melanin granules (modified Wright’s stain; original magnification, 1000×). Melanin granules (white arrow) are frequently mistaken for rod-shaped bacteria. Note that the granules are not in chains or clumps but are organized in a haphazard fashion. Melanin granules are often refractile when examined using the fine focus knob of the microscope; note that the granules are light greenish-brown, whereas bacteria would take on a purple color when stained.

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Editor's note: This article was originally published in June 2016 as "Image Gallery: Ear Cytology"