Masses of the Meckel Cave

Meckel cave tumors are usually asymptomatic and can be followed if characteristically benign findings are seen on MRI or CT. Differential considerations for masses in the Meckel cave include:

• Trigeminal schwannoma: The case shown above. Relatively rare. Can be seen with neurofibromatosis type 2 or as an isolated entity. Smooth margins, usually low on T1 and high on T2. Avid enhancement with or without cystic components.
• Epidermoid tumor: Arise from incomplete cleavage of neural ectoderm from cutaneous ectoderm and grow by desquamation of epithelial cells. Lobulated margins, Low on T1 and high on T2, minimal mass effect.
• Meningioma: Isointense to surrounding normal brain parenchyma on T1- and T2-weighted images. May calcify.
• Trigeminal lipoma: Rare. Looks like fat. Infiltrates the trigeminal nerve fascicles.
• Primary lymphoma: Can mimic trigeminal schwannoma. Consider this diagnosis in immunocompromised patients. The presence of an apparent dural tail can suggest lymphoma in the absence of hyperostosis (typically seen with meningiomas).
• Arachnoid cyst: Fluid signal on all sequences.
• Chordoma: Arises from adjacent clivus.

References

• Abdel Aziz KM, van Loveren HR. Primary lymphoma of Meckel's cave mimicking trigeminal schwannoma: case report. Neurosurgery. 1999 Apr;44(4):859-62; discussion 862-3.
• Beck DW, Menezes AH. Lesions in Meckel's cave: variable presentation and pathology. J Neurosurg. 1987 Nov;67(5):684-9.
• Yuh WT, Wright DC, Barloon TJ, Schultz DH, Sato Y, Cervantes CA. MR imaging of primary tumors of trigeminal nerve and Meckel's cave. AJR Am J Roentgenol. 1988 Sep;151(3):577-82.