Hypothalamus Lesion



Hypothalamus Lesion


Anne G. Osborn, MD, FACR



DIFFERENTIAL DIAGNOSIS


Common



  • Pilocytic Astrocytoma


  • Diffuse Astrocytoma, Low Grade


Less Common



  • Craniopharyngioma


  • Germinoma


  • Neurosarcoid


  • Langerhans Cell Histiocytosis


  • Lipoma


  • Lymphocytic Hypophysitis


  • Metastases



    • Hypothalamic/Pituitary Axis Metastases


    • Lymphoma


    • Leukemia


  • Tuber Cinereum Hamartoma


  • Ectopic Posterior Pituitary


Rare but Important



  • Other Gliomas



    • Chordoid Glioma


    • Pilomyxoid Astrocytoma


    • Pituicytoma


    • Ganglioglioma


  • Demyelinating Disease



    • Multiple Sclerosis


    • ADEM


  • Wernicke Encephalopathy


  • Cavernous Malformation


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Anatomic essentials



    • Hypothalamus lies below level of anterior, posterior commissures


    • Inferior hypothalamus formed by



      • Anterior recesses of 3rd ventricle


      • Tuber cinereum


      • Mamillary bodies


      • Infundibular stalk


  • Differentiating features of hypothalamic lesions based on



    • Precise anatomic sublocation (e.g., infundibulum)


    • Patient age


    • Clinical presentation


    • CT/MR features (density/signal intensity, enhancement, Ca++)


Helpful Clues for Common Diagnoses



  • Astrocytoma



    • Most common primary neoplasm of hypothalamic-optic chiasm region


    • Usually low grade (pilocytic > WHO grade II fibrillary)


    • Age < 5 years


    • Endocrine dysfunction in 20%


    • Look for evidence for NF1



      • 20-50% of patients with pilocytic astrocytoma


Helpful Clues for Less Common Diagnoses



  • Craniopharyngioma



    • Second-most common suprasellar mass in children


    • Occurs anywhere from intrasellar to stalk to anteroinferior 3rd ventricle


    • 90% calcify, 90% have multiple cysts (mixed signal intensity), 90% calcify


  • Germinoma



    • Can be primary in hypothalamus/stalk



      • M = F (vs. male predominance in pineal gland)


    • 10% “double” midline lesions (pineal & hypothalamus)


    • DI, diencephalic syndrome, precocious puberty common


    • Thick enhancing stalk, 3rd floor, absent posterior pituitary “bright spot”


  • Neurosarcoid



    • Adult with stalk, meningeal lesions


    • Other infectious/inflammatory lesions that can mimic sarcoid



      • Wegener granulomatosis


      • TB, syphilis


  • Langerhans Cell Histiocytosis



    • Stalk/hypothalamus lesion in a child


  • Lipoma



    • Lipoma: Sessile T1 hyperintense lesion on subpial surface of hypothalamus


    • Osteolipoma: Rare; fat density/signal intensity & calcification


  • Lymphocytic Hypophysitis



    • Peripartum female most common


    • Can mimic macroadenoma


  • Metastases



    • Hypothalamic/Pituitary Axis Metastases



      • 1-25% of systemic cancers at autopsy


      • Less common at imaging


      • Breast, lung most common primary tumors



    • Lymphoma



      • Pituitary/stalk/hypothalamus uncommon site


      • Can be primary or metastatic


    • Leukemia



      • Often involves dura, paranasal sinuses


  • Tuber Cinereum Hamartoma



    • Children with gelastic seizures, males with isosexual precocious puberty


    • Can be pedunculated or sessile


    • Density/signal intensity typically isointense with cortex


    • No Ca++, enhancement


    • Sessile lesion may be difficult to distinguish from hypothalamic astrocytoma (no change on follow-up)


Helpful Clues for Rare Diagnoses



  • Other Gliomas



    • Chordoid Glioma



      • Floor of 3rd ventricle


      • Hyperintense with strong, uniform enhancement


    • Pilomyxoid Astrocytoma



      • Infant/young child


      • “H”-shaped tumor of hypothalamus; extension into medial temporal lobes common


      • Often large, bulky, ± hemorrhage (rare in pilocytic astrocytoma)


      • ± Hemorrhage (25% of PMAs; rare in pilocytic astrocytoma)


    • Pituicytoma



      • Stalk, posterior pituitary lobe


      • Low grade astrocytoma


      • Enhances strongly, uniformly


    • Ganglioglioma



      • Very rare in hypothalamus/chiasm


      • Young adult (mean age = 20 years)


  • Demyelinating Disease

Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Hypothalamus Lesion
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