Clinical and Imaging Findings in Four Patients with the Diagnosis of PmA Compared with that of Chiasmatic/Hypothalamic PA

MR CharacteristicsPmA PatientsTypical PA in Chiasmatic/Hypothalamic Region
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Composition solid versus cystic>70% solid>90% solid100% solid100% solidMostly solid possibly cystic
Mass effect and encasement of surrounding vessels at time of presentationModerateExtensiveExtensiveModerateMild to moderate
T1 signal intensityHypointenseHypointenseHypointenseHypointenseHypointense, cystic portion CSF isointense
T2 signal intensityHyperintenseHyperintenseHyperintenseHyperintenseHyperintense
Contrast enhancement of solid portion and cyst wallHomogenous and thick peripheral enhancementHomogenousHomogenousHomogenousVariable, may not enhance
Basilar meningeal enhancementNoYesYesYesNo
Spinal meningial enhancementn/aYesYesn/aNo
Extension of T2 to deep gray/white matterYesNoNoYesYes
Location (optic chiasm/hypothalamus)Optic chiasm/hypothalamusOptic chiasm/hypothalamusOptic chiasm/hypothalamusOptic chiasm/hypothalamusOptic chiasm/hypothalamus
Calcification, ossificationNoNoNoNoYes (10%)
HydrocephalusYes (mild to moderate)NoneMild (slight prominence temp. horns)NoneMild
NecrosisNoNoYesYesNo
HemorrhageNoNoNoNoNo
Association with neurofibromatosis 1NoNoNoNoYes
Age at presentation/sex2 years/boy5 months/boy2 years/girl10 months/boyChildhood (2–6 years)
Clinical presentationFailure to thriveFeeding difficultiesFailure to thriveDevelopmental delayNonspesific, similar to PMA