Preauricular Sinuses Workup

Updated: Jan 27, 2020
  • Author: Jeffrey Weinberg, MD; Chief Editor: William D James, MD  more...
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Laboratory Studies

If exudate from the sinus is present, culturing should be performed so that antibiotic therapy tailored to the offending pathogen can be instituted. In 2002, Martin-Granizo et al [16] suggested that initial fistula probing serves as a surgical guide and further methylene blue infection helps to avoid leaving viable squamous epithelial remnants.


Imaging Studies

Ultrasonography readily depicts preauricular sinuses and demonstrates their relationship to the superficial temporal artery, the anterior crus of the helix, and the tragus.

In patients with isolated preauricular sinuses or tags, ultrasound should not be done as a matter of course to rule out urinary tract of kidney anomalies in children without other a high index of clinical suspicion. [17]


Histologic Findings

Upon gross examination, the preauricular sinuses are seen to consist of tubular structures of simple or arborized patterns having walls, which may be thin and glistening or white and thickened. The sinus tract may arborize and can be tortuous, and the lumen is filled with debris. The preauricular sinuses are often full of keratin and are surrounded by dense connective tissue.

Microscopically, the duct of the sinus is lined with stratified squamous epithelium and contains many cysts along its tract. The connective tissue surrounding the duct may contain hair follicles; sebaceous and sweat glands; and inflammatory tissue, such as lymphocytes, plasma cells, and polymorphonuclear leukocytes.