Olfactory neuroepithelium in the superior and middle turbinates: which is the optimal biopsy site?

Introduction: Olfactory neuroepithelium (ON) biopsy has several therapeutic applications for both disorders of olfaction and neurodegenerative diseases. Successful collection of ON is still anything but routine due to a dearth of studies on the distribution of ON in the superior and middle turbinates. Aim: To determine the location in which ON is most likely to be present in endoscopically removed cadaver superior and middle turbinates as well as the influences of gender, age, and naris side on the presence of ON and the extent to which it is present. Methods: We conducted a prospective anatomical study. The superior and middle turbinates on both sides endoscopically removed from 25 fresh cadavers (less than 12 h post-mortem). The turbinates were halved into anterior and posterior segments for a total of 200 specimens, which were analyzed after hematoxylin and eosin and immunohistochemical staining. Hematoxylin and eosin-stained slides were subjected to blind examination by 3 independent pathologists, and the presence of ON was graded on a 5-point scale from 0 to 4. Kappa measurement was used to determine the agreement between pairs of observers. Results: ON was present in 82.9% of superior turbinate samples and in 17.1% of middle turbinate samples. Immunohistochemistry detected ON in superior turbinates only by S-100 staining and only in 15 fragments. Gender, age, and naris side had no statistically significant effects on the presence of ON. Conclusion: When biopsying ON, the posterior portion of the superior turbinate should be targeted whenever possible because it has the highest concentration of ON among the nasal structures.