This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Glomus tumor invading the veical pa of carotid canal. It is 
Select and explain. 
A. Type B, B. Type CI, C. Type C2, D. Type C3
C: Type C2
Answer: C: Type C2 
Explanation: Ans. is 'c' i.e., Type C2 Fisch classification The Fisch classification of glomus tumors is based on extension of the tumor to surrounding anatomic structures and is closely related to moality and morbidity. Type A :- Limited to middle ear cleft (glomus tympanicum). Type B :- Limited to tympanomastoid area with no involvement of infralabyrinthine compament. Type C :- Involving infralabrinthine compament extending upto petrous apex Type C1 :- Limited involvement of veical poion of carotid canal Type C2 :-Invading veical poion of carotid canal Type C3 :-Invasion of horizontal poion of carotid canal Type D Intracranial extension Type D1 Intracranial extension < 2 cm in diameter Type D2 :-Intracranial extension > 2 cm in diameter