PT  - JOURNAL ARTICLE
AU  - J.M. Pascual
AU  - R. Carrasco
AU  - L. Barrios
AU  - R. Prieto
TI  - Duct-like Recess in the Infundibular Portion of Third Ventricle Craniopharyngiomas: An MRI Sign Identifying the Papillary Type
AID  - 10.3174/ajnr.A7602
DP  - 2022 Aug 11
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2022/08/11/ajnr.A7602.short
4100  - http://www.ajnr.org/content/early/2022/08/11/ajnr.A7602.full
AB  - BACKGROUND AND PURPOSE: Papillary craniopharyngiomas (PCPs) are particularly challenging lesions requiring accurate diagnosis to plan the best therapy. Our aim was to define a narrow duct-like recess identified on MR imaging at the base of papillary craniopharyngiomas with a strict third ventricle location.MATERIALS AND METHODS: A duct-like recess at the infundibular portion of craniopharyngiomas was observed on conventional T1WI and T2WI in 3 strict third ventricle papillary craniopharyngiomas in our craniopharyngioma series (n = 125). We systematically investigated this finding on the MR imaging of 2582 craniopharyngiomas and 10 other categories of third ventricle tumors (n = 690) published in the modern era (1986–2020). The diagnostic value and significance of this finding are addressed.RESULTS: The duct-like recess was recognized in 52 papillary craniopharyngiomas, including 3 of our own cases, as a narrow canal-shaped cavity invaginated at the tumor undersurface, just behind the optic chiasm. This structure largely involves papillary craniopharyngiomas with a strict third ventricle topography (96%), follows the same diagonal trajectory as the pituitary stalk, and finishes at a closed end. The duct-like recess sign identifies the papillary craniopharyngioma type with a specificity of 100% and a sensitivity of 38% in the overall craniopharyngioma population. This finding can also establish the strictly intra-third ventricle location of the lesion with a 90% specificity and 33% sensitivity. These recesses appear as hypointense circular spots on axial/coronal T1WI and T2WI. Their content apparently corresponds to CSF freely flowing within the suprasellar cistern.CONCLUSIONS: The presence of a duct-like recess at the infundibular portion of a third ventricle tumor represents a distinctive hallmark of papillary craniopharyngiomas that can be used as a simple MR imaging sign to reliably diagnose these lesions.ACPadamantinomatous craniopharyngiomaCPcraniopharyngiomaCP-DRCPs with a basal duct-like recessCP-nDRCPs without a basal duct-like recessDRduct-like recessPCPpapillary craniopharyngiomaPSpituitary stalk3Vthird ventricle3VFthird ventricle floor