Open- and closed-type congenital cholesteatomas of the middle ear: computed tomography differentiation and correlation with surgical staging.

Abstract

Purpose: To investigate the differences in computed tomography (CT) features between closed-type congenital cholesteatoma (CCC) and open-type congenital cholesteatoma (OCC) of the middle ear and to evaluate the usefulness of preoperative CT examination for staging workup of congenital cholesteatoma (CC) in correlation with the surgical findings.

Methods: We retrospectively reviewed the preoperative CT scans of the temporal bone obtained from 80 patients with surgically confirmed CC of the middle ear. All patients had a solitary lesion, except for one patient with two lesions, resulting in 81 CCs, which formed the basis of this study. We compared the CT features between CCCs and OCCs, focusing on their morphological characteristics, such as size, shape, location, and bone change. Based on the Potsic classification, the stage of CCs was determined at CT and surgery, and the results were compared between CCCs and OCCs.

Results: Of the 81 CCs, surgery revealed 43 CCCs and 38 OCCs. On CT scans, CCC was frequently seen as a small (median: 3.15 mm), round to oval (65.1%) mass, most commonly located in the anterosuperior quadrant (74.4%) of the middle ear with less frequent ossicular erosion (14.0%). In contrast, OCC was frequently seen as a large (median: 6.70 mm), irregular (94.7%) mass, most commonly located in the posterosuperior quadrant (68.4%) of the middle ear with frequent ossicular erosion (55.3%). The size, shape, location, and presence of ossicular erosion were significantly different between the two types. Overall, the CT and surgical stages of CCs demonstrated good agreement (kappa value: 0.77) and the CT and surgical stages of OCCs were statistically significantly higher than those of CCCs (P < 0.001 in both).

Conclusion: CT is useful for preoperative determination of the types and staging of CC of the middle ear.

Clinical significance: Preoperative differentiation between CCC and OCC is important to avoid reoperation and prevent an extensive surgery. By providing valuable information on the morphology and extent of the lesions, CT is useful for not only the accurate preoperative determination of the type of CCs but also the accurate prediction of staging of the lesion, which should be important to preparing optimal treatment plans.