Do maxillary sinus retention cysts reflect obstructive sinus phenomena?

Objective: To determine the relation of maxillary sinus retention cysts (RCs) to ostiomeatal complex (OMC) obstruction and anatomic variation of the paranasal sinuses. Methods: The results of 410 computed tomographic scans of the sinuses ordered by otolaryngologists in an academic center during a 1-year period were reviewed. Computed tomographic scans with maxillary sinus RCs were studied to determine cyst characteristics, the Lund score, OMC size and patency, and the presence of anatomic variations. Statistical analysis was conducted to determine the relation of RCs to these factors. Results: The incidence of RCs was 12.4% (51 cases). The mean patient age was 41.3 years, with a female-male ratio of 2.4:1. Nine cases demonstrated bilateral cysts, allowing 42 unilateral cases to be analyzed with the nondiseased side as a control. The mean cyst size was 1.56 cm, and cysts were most commonly located inferiorly (30 [50%]) and were solitary (45 [88%]). The RC side had a higher mean Lund score than the control side (2.62 vs 1.93; P=.008, Wilcoxon signed rank test). Of the cyst sides, 18 (43%) demonstrated OMC occlusion, vs 15 (36%) for the control side (P=.55, McNemar test). The mean OMC size was smaller for the cyst side vs the control side (0.77 vs 1.35 mm; P=.13). No association was found between RCs and concha bullosa or Haller cells (P=.45 and P=.39, respectively). Conclusions: Maxillary sinus RCs do not reflect persistent obstructive pathology of the OMC, and are not associated with potentially obstructive anatomic sinus variations. Consideration should be given to not scoring RCs as positive disease during Lund staging.