OBJECTIVE: To define the difference of meningiomas that originate in t
he area of Meckel's cave (MC) (primary MC meningiomas) in regard to th
e different surgical approaches and postoperative results. METHODS: A
retrospective analysis of all meningiomas involving the cranial base d
isplayed 21 cases of meningiomas originating in MC (primary MC meningi
omas). These cases were classified according to the tumor extension in
four different types: Type I, tumors mainly confined to MC; Type II,
MC meningiomas with extension into the middle fossa; Type III, MC meni
ngiomas with extension into the posterior fossa; and Type IV, MC menin
giomas with extension into both middle and posterior fossae. RESULTS:
Trigeminal neuralgia resolved in all cases in this series, despite tum
or type. Trigeminal hypesthesia showed postoperative improvement only
in Type III MC meningiomas. In Types I and III, total removal without
further morbidity was frequently achieved. Cavernous sinus infiltratio
n, especially in Types II and IV, limited (in some cases) the extent o
f tumor extirpation. CONCLUSION: Types I, II, and III MC meningiomas h
ave a good prognosis. In most cases, very good outcomes are achieved.
Radical tumor removal can usually be achieved without further morbidit
y and with postoperative improvement of the preexisting symptoms, espe
cially in Types I and III MC meningiomas. On the contrary, Type IV MC
meningiomas are usually only subtotally resected. Surgery in such case
s may carry a high risk of additional morbidity, especially with regar
d to the IIIrd, IVth, and VIth cranial nerves. The postoperative outco
me regarding facial pain in cases of all tumor types is usually very g
ood. Trigeminal hypesthesia may persist after tumor removal in the maj
ority of cases.