On the classification of the petrous pyramid cholesteatoma
Anikin I.A.¹, Khamgushkeeva N.N.¹, Ilin S.N.¹, Bokuchava T.A.<sup>2

1</sup> Saint-Petersburg Scientific Research Institute of Ear, Nose, Throat and Speech
² Murmansk Regional Clinical Hospital named after P.A. Bayandin

Cholesteatoma is the tumor formed by keratinizing epithelium, keratin residues and perimatrix of various thicknesses with or without surrounding inflammatory reaction. In 2.9% of patients with cholesteatoma it spreads to the petrous pyramid. Aggressive growth of the petrous pyramid cholesteatoma can lead to the destruction of the underlying bone structures with the spread of the tumor to the clivus, the sphenoid sinus, the infratemporal fossa, the nasopharynx with possible penetration into the subdural space.
Aim: the detailed classification of the petrous pyramid cholesteatoma.
Patients and Methods: this prospective study included 22 patients with chronic suppurative otitis media who had a petrous pyramid cholesteatoma. The diagnosis is based on an otolaryngological examination, multispiral computed tomography (MSCT) of temporal bones, MRI of the middle ear, diffuse-weighted MRI of the brain. The average age of the patients was 39.2 ± 7 years. The Moffat-Smith 2008 classification of the petrous pyramid cholesteatoma was used in the work.
Results: MSCT of the temporal bone reveals various destructive processes with high accuracy and specificity, that is important for determining the boundaries of  the tumor and thus the classification of the petrous pyramid cholesteatoma. Based on CT images and updated Moffat-Smith petrous pyramid cholesteatoma classification, depending on the location in relation to the labyrinth the tumors were distributed on the supra-labyrinth (n-9), supra-labyrinth-apical (n-3), infra-labyrinth (n-3), infra-labyrinth-apical (n-5), massive labyrinth (n-1) and massive labyrinth petrous pyramid cholesteatoma with apical proliferation (n-1).  Thus, in this article we have attempted to describe the boundaries of various types of the petrous pyramid cholesteatoma on the basis of the MSCT of the temporal bones.
Conclusion: the use of the proposed classification will provide an opportunity to determine the type of the petrous pyramid cholesteatoma and will help in choosing the tactics of surgical treatment of this pathology.

Key words: the petrous pyramid cholesteatoma, chronic suppurative otitis media, classification, computed tomography.
For citation: Anikin I.A., Khamgushkeeva N.N., Ilin S.N., Bokuchava T.A. On the classification of the petrous pyramid cholesteatoma // RMJ. 2017. № 23. P. 1698–1702.