Imaging Findings in Auto-Atticotomy

Abstract

BACKGROUND AND PURPOSE:An acquired attic cholesteatoma may spontaneously drain externally into the external auditory canal, leaving a cavity in the attic with the shape of the original cholesteatoma but now filled with air, a phenomenon referred to as "nature's atticotomy" or auto-atticotomy. We describe and quantify the CT appearance of the auto-atticotomy cavity as it pertains to the appearance of the scutum and the lateral attic wall.

An Incidental Case of Auto-atticotomy

“…This may result in erosion of the lower lateral wall of the attic and the scutum [21,22], resulting in spontaneous drainage into the external auditory canal known as auto-atticotomy, with an air filled cavity remaining, which reflects the dimensions of the cholesteatoma [2,23]. This bony destruction likely result from a combination of different mechanisms, mass effect of the growing cholesteatoma, cytokines secreted within the environment, and osteoclastic activity of the cholesteatoma [23].…”

“…Typical findings include an expansile soft-tissue lesion with associated retraction of the tympanic membrane. This in turn leads to blunting of the scutum and erosion of the ossicles [2]. MRI imaging with Diffusion Weighted Imaging (DWI) may also be performed in cases where tissue differentiation is helpful for diagnosis [15].…”

“…Primary acquired cholesteatoma or retraction pocket cholesteatomata, most commonly forms in the Prussak's space lateral to the ossicles [2], with lateral expansion. This may result in erosion of the lower lateral wall of the attic and the scutum [21,22], resulting in spontaneous drainage into the external auditory canal known as auto-atticotomy, with an air filled cavity remaining, which reflects the dimensions of the cholesteatoma [2,23].…”

“…In a minority of patients a spontaneous atticotomy may occur, called auto-atticotomy, where there is spontaneous drainage of the cholesteatoma into the external auditory canal [2].…”

“…Cholesteatoma is a nonmalignant cyst like growth consisting of squamous epithelium that is located in the middle ear or mastoid air cells which can lead to the erosion of structures within the temporal bone [1][2][3]. This may then lead to central nervous system complications, which in turn may be potentially fatal [4][5][6].…”