Radiological features of craniopharyngiomas located in the posterior fossa.

BACKGROUND AND PURPOSE: Posterior fossa craniopharyngiomas (PFCP) constitute 1.6-4% of all craniopharyngiomas and have long been neglected. The purpose of our study was to investigate neuroimaging features of this unique modality in a cohort of 7 cases.

METHODS: CT and/or MR imaging features (with and without contrast enhancement) of 7 patients who underwent craniotomies for histologically proved PFCP were reviewed and analyzed retrospectively. Surgical management was also reviewed.

RESULTS: All PFCPs arised from sellar/suprasellar region and extended into unilateral cerebellopontine angle in 6 cases, and bilateral in 1 case. Seven tumors were of retrochiasmatic origin and 5 of 7 were of retrostalk growth pattern with location in the ventral area of brain stem. On CT scans, tumors were isodense in solid component and hypodense in cystic component with (4/7) or without calcification (3 /7) and destruction in sellae turcia (2/7). Tumors demonstrated cyst formation (7/7) with hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging in 5 cases, hyperintense both on T1- and T2-weighted imaging in 2 cases. The solid components and capsule revealed mild to moderate inhomogeneous enhancement after administration of contrast agents. Total tumor removal was accomplished in 5 cases, subtotal removal and partial removal in 1 case respectively.

CONCLUSIONS: PFCPs are well demarcated, contrast-enhanced tumors, typically with cystic parts or purely cyst. Most of PFCPs demonstrate a retrostalk growth pattern and characteristic connection. Tumor with cystic component arises from sellar region and then extends to posterior fossa, which should be strongly suspected as a PFCP. The combined supra- and infratentorial approach is an ideal choice for surgical management of PFCP.