FINAL DIAGNOSIS : Hypothalamic Hamartoma

They were said to have signal intensity similar to normal cortex on all sequences, this is in fact not true in most cases 7.

  1. T1
    • hypointense to the cerebral cortex (74%) 7
  2. T1 C+ (Gd): no contrast enhancement
  3. T2
    • hyperintense to the cerebral cortex (93%) 7
    • hyperintensity is more conspicuous on FLAIR
    • the higher the proportion of glial cells, the higher the T2 signal 3
  4. MR spectroscopy
    • reduced NAA/Cr
    • increased myoinositol 3
    • increased Cho/Cr compared to the amygdala has also been reported 

Delalande Classification of Hypothalamic Hamartomas

  • Type I lesions have horizontal attachment inferior to floor of the third ventricle. 
  • Type II lesions have vertical attachment to the wall of third ventricle and are above the floor of the third ventricle. 
  • Type III lesions have horizontal and vertical attachments above and below the floor of the third ventricle. 
  • Type IV lesions are considered “giant” with volume 8 cm3 or larger

The differential diagnosis is broadly that of suprasellar/hypothalamic lesions, although the imaging characteristics of hypothalamic hamartomas significantly reduce the differential.

Hypothalamic-chiasmatic glioma is the main differential. Most other lesions encountered in the region either have markedly different signal intensity or demonstrate enhancement.

T1 Axial
T2 Saggital
Post contrast T1 saggital