Which of the following structures is not at immediate risk of erosion by cholesteatoma: (A) Long process of incus, (B) Fallopian canal containing facial nerve, (C) Horizontal/ lateral semicircular canal, (D) Basal plate of stapes
Answer is D. An attic cholesteatoma may extend backwards into the aditus, antrum and mastoid; downwards into the mesotympanum; medially, it may surround the incus and/or head of malleus. Cholesteatoma has the propey to destroy bone. It may cause destruction of ear ossicles, erosion of bony labyrinth, canal of facial nerve, sinus plate or tegmen tympani and thus cause several complications. Ref: Dhingra 7e pg 74.