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case_images: Preoperative endoscopic finding. There were whitish round mass in right (A) and left (B) anterior superior tympanic membrane. Otherwise, there was no abnormality in both middle ear cavity.
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case_images: On the endoscopic examination, a whitish mass was observed in the anterior superior quadrant of the tympanic membrane on both ear (Fig. 1), and the hearing threshold confirmed by play audiometry showed 21 dB in the right (Rt) side and 23 dB in the left (Lt) side (Fig. 2).
case_images: Axial view (A) and coronal view (B) of CT scan shows bilateral round mass in both middle ear cavity. The mass were observed at same level in CT scan, and they were symmetrically located in anterior medial part of malleus. Right mass (white arrow) was 2.5x3 mm and left mass (blue arrow) was 3.5x3 mm sized. CT, computed tomography.
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case_images: Temporal bone computed tomography (CT) of the Rt ear showed a 2.5x3 mm sized round mass in the anterior portion of the malleus, and the Lt ear showed 3.5x3 mm sized round mass in the symmetrical location (Fig. 3).
case_images: Operative finding of right ear. (A) The mass (arrow) was located under the malleus handle. The origin of mass was cochleariform process (asterisk). (B) The mass was clearly removed without remnant tissue.
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case_images: Operational findings of both ears were the same, 3 mm-sized well capsulated cholesteatoma originating from cochleariform process were observed in both the Rt (Fig. 4) and Lt (Fig. 5) side (Fig. 6).
case_images: Specimen photo. Specimen from right (black arrow) and left (blue arrow) middle ear cavity. There were symmetric 3 mm sized round whitish mass without adhesion to middle ear mucosa.
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case_images: Operational findings of both ears were the same, 3 mm-sized well capsulated cholesteatoma originating from cochleariform process were observed in both the Rt (Fig. 4) and Lt (Fig. 5) side (Fig. 6).
case_images: Pathologic finding. Keratin tissues (asterisk) with cystic components (black arrow) were observed in both right (A) and left (B) specimen (H&E, x40). Both right (C) and left (D) specimens showed intact epithelial lining (blue arrow) without evidence of foreign body reaction, suggesting closed type cholesteatoma (H&E, x100). Scale bar=200 microm.
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case_images: Closed type cholesteatoma was confirmed by post-operative pathology report (Fig. 7).
case_images: Postoperative endoscopic finding after 2 month. Both right (A) and left (B) tympanic membrane were well formed after operation.
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case_images: The endoscopic exam two months after the operation showed well adapted tympanic membrane without any evidence of recurrence (Fig. 8), and the audiometry confirmed the maintenance of hearing (Fig. 9).