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Ross
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---
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title: "Hypothalamic Hamartoma"
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docid: "7f85487f-9497-44a9-b884-b98e50d41018"
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breadcrumbs:
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- "Brain"
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- "Diagnosis"
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- "Anatomy-Based Diagnoses"
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- "Sella and Pituitary"
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- "Congenital"
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- "Hypothalamic Hamartoma"
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---
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# KEY FACTS
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- ## Terminology
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- a.k.a. tuber cinereum hamartoma
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- Nonneoplastic; congenital gray matter heterotopia
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- ## Imaging
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- Hypothalamic mass contiguous with tuber cinereum
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- Located between mammillary bodies and infundibulum
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- Can be sessile or pedunculated ("collar button")
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- Size ranges from few mm to several cm
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- Isointense with gray matter on T1WI
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- Can be slightly hyperintense on T2/FLAIR
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- Large lesions can be heterogeneous, contain cysts
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- No enhancement on T1 C+
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- ## Top Differential Diagnoses
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- Chiasmatic/hypothalamic astrocytoma
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- Craniopharyngioma
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- Ectopic posterior pituitary
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- Lipoma
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- Germinoma
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- Langerhans cell histiocytosis
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- ## Pathology
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- Mature but dysplastic neuronal ganglionic tissue
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- ## Clinical Issues
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- Infant with epilepsy or precocious puberty
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- Cognitive, neuropsychiatric comorbidities common
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- Older children with precocious puberty
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- Often tall, overweight, with advanced bone age
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- Shape, size of hamartoma often predicts symptoms, presentation
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- Large, sessile lesions → seizures
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- Small, pedunculated lesions → central precocious puberty
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- ## Diagnostic Checklist
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- If hypothalamic mass in seizure imaging, think hypothalamic hamartoma; if enhancement present, consider astrocytoma
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# TERMINOLOGY
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- ## Synonyms
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- Tuber cinereum hamartoma, diencephalic hamartoma
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- ## Definitions
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- Nonneoplastic congenital gray matter heterotopia in region of tuber cinereum of hypothalamus
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# IMAGING
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- ## General Features
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- ### Best diagnostic clue
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- Nonenhancing hypothalamic mass contiguous with tuber cinereum
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- ### Location
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- Tuber cinereum of hypothalamus
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- Located between pons/mammillary bodies and hypothalamic infundibulum
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- ### Size
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- Variable, few mm to giant (3-5 cm)
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- ### Morphology
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- Sessile or pedunculated mass
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- Similar in density/intensity to gray matter
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- ## Radiographic Findings
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- ### Radiography
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- ± suprasellar calcifications, eroded dorsum, enlarged sella (rare)
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- ## CT Findings
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- ### NECT
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- Homogeneous suprasellar mass
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- Isodense → slightly hypodense
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- Cysts and calcification are uncommon
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- ± patent craniopharyngeal canal (very rare)
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- ### CECT
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- No pathologic enhancement
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- ## MR Findings
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- ### T1WI
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- Mass located between mammillary bodies and infundibulum
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- Isointense → slightly hypointense to gray matter
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- ### T2WI
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- Isointense → slightly hyperintense (secondary to fibrillary gliosis)
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- ### PD/intermediate
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- Hyperintense to CSF, slightly hyperintense to gray matter
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- ### FLAIR
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- Isointense → slightly hyperintense to gray matter
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- ### T1WI C+
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- Nonenhancing; if enhancing, consider other diagnosis
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- ### MRS
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- ↓ NAA and NAA/Cr, mild ↑ Cho and Cho/Cr, ↑ myoinositol (mI) and mI/Cr
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- ↓ NAA and ↑ Cho indicate reduced neuronal density and relative gliosis, respectively, compared to normal gray matter
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- ↑ mI/Cr correlates with ↑ glial component and lesion T2 hyperintensity
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- ## Imaging Recommendations
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- ### Best imaging tool
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- Multiplanar MR imaging
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- ### Protocol advice
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- Thin-section sagittal and coronal T2W1, T1WI C+ MR
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# DIFFERENTIAL DIAGNOSIS
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- [Craniopharyngioma](/document/craniopharyngioma/00e66680-6731-4287-b5a1-3f0b3f09053b)
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- Most common suprasellar mass in children
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- Variable signal intensity cysts (90%), calcifications (90%), and enhancement (90%)
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- Longstanding lesion, frequently with short stature and pituitary abnormalities
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- ## Chiasmatic/Hypothalamic Astrocytoma
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- 2nd most common pediatric suprasellar mass [± neurofibromatosis type 1 (NF1)]
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- Hyperintense on T2WI MR ± contrast enhancement (heterogeneous, often vigorous)
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- Optic pathway or hypothalamus ± optic tract extension
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- ## Ectopic Posterior Pituitary
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- Ectopic hyperintense focus on T1WI MR
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- Often located along median eminence of hypothalamus
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- No normal orthotopic posterior pituitary hyperintensity
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- [Germinoma](/document/germinoma/078b68a2-67de-457e-818a-63655cec95aa)
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- Thickening, abnormal enhancement of pituitary stalk rather than tuber cinereum
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- Diabetes insipidus common
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- ± multicentric: Suprasellar, pineal, thalamus, basal ganglia
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- Early leptomeningeal metastatic dissemination
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- [Langerhans Cell Histiocytosis](/document/langerhans-cell-histiocytosis-skul-/5bfd61b0-b320-46f4-b785-6c69daa8523c)
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- Thickening, abnormal enhancement of pituitary stalk rather than tuber cinereum
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- Diabetes insipidus common
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- Look for lytic bone lesions in typical locations
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- [Lipoma](/document/lipoma-brain/1bdb974e-8346-4730-9b1c-dea7b70b844d)
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- Hyperintense fat signal on T1WI MR
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- Hypointense on STIR or fat-saturated sequences
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# PATHOLOGY
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- ## General Features
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- ### Etiology
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- Neuronal migration anomaly (occurs between gestational days 33-41)
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- Affects normal hypothalamic regulation of autonomic, endocrine, neurologic, behavioral functions
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- Pathogenesis of precocious puberty-induced sexual precocity
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- ± luteinizing hormone-releasing hormone (LHRH) granules in hamartoma/connecting axons in some
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- Activating astroglial-derived factors in tumors may stimulate endogenous LHRH secretion if no intratumoral LHRH granules
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- Shape and size of hamartoma postulated to predict symptoms
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- Large, sessile lesions → seizures
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- Small, pedunculated lesions → central precocious puberty (CPP)
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- Presentation with both seizures and CPP common
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- ### Genetics
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- *GLI3*mutation
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- Pallister-Hall syndrome (PHS)
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- Hamartoma or hamartoblastoma of tuber cinereum; often large mass
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- Digital malformations (short metacarpals, syndactyly, polydactyly)
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- Other midline (epiglottis/larynx) and cardiac/renal/anal anomalies
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- Greig cephalopolysyndactyly syndrome (GCPS)
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- ## Staging, Grading, & Classification
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- Valdueza classification
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- Pedunculated, CPP or asymptomatic
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- Originates in tuber cinereum
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- Originates in mammillary bodies
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- Sessile, hypothalamus displaced, seizures
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- More hypothalamic dysfunction and abnormal behavior
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- ## Gross Pathologic & Surgical Features
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- Mature neuronal ganglionic tissue projecting from hypothalamus, tuber cinereum, or mammillary bodies
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- Pedunculated or sessile, rounded or nodular
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- ## Microscopic Features
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- Well-differentiated neurons interspersed with glial cells, myelinated/unmyelinated axons, variable amounts of fibrillary gliosis
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- Hamartoblastomas include primitive undifferentiated cells
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- Rare reports of cysts, necrosis, calcifications, fat
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# CLINICAL ISSUES
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- ## Presentation
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- ### Most common signs/symptoms
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- Luteinizing hormone-releasing hormone (LHRH) dependent CPP presenting at very young age
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- Refractory symptomatic mixed seizure types, including gelastic seizures
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- Gelastic seizures are recurrent automatic bursts of laughter without mirth
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- Presentation usually encompasses both epileptic seizures and encephalopathy with behavioral cognitive impairment
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- May progress to partial epilepsy, partial complex seizures, generalized tonic clonic seizures
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- Rarely occur in conjunction with focal cortical dysplasia or hypothalamic astrocytoma
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- Other seizure types frequent with hypothalamic hamartoma (HH); always look for HH in child with epilepsy
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- ### Other signs/symptoms
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- Depression, anxiety common in adult HH patients
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- ### Clinical profile
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- Infant with gelastic seizures or precocious puberty
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- Older children with precocious puberty; tall, overweight, and advanced bone age
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- ## Demographics
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- ### Age
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- Usually present between 1-3 years of age
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- ### Sex
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- No predilection; some reports M > F
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- ### Ethnicity
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- No predilection
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- ### Epidemiology
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- Of histologically verified lesions, 3/4 have precocious puberty and 1/2 have seizures
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- Up to 33% of patients with CPP have HH
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- ## Natural History & Prognosis
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- Size should remain stable; if growth is detected, surgery/biopsy is indicated
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- Postsurgical hypothalamic complications include headache, mental slowing, and weight gain
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- Symptomatic lesions: Sessile > > pedunculated
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- Sessile lesions nearly always symptomatic
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- Syndromic patients generally do poorly
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- ## Treatment
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- Medical: Hormonal-suppressive therapy, treat seizures
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- Surgical: If medical therapy failure or rapid lesion growth
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- Endoscopic or transcallosal surgical resection
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- Recent studies have shown stereotactic laser ablation to have equivalent efficacy to open surgery with fewer complications
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- Stereotactic radiosurgery and Gamma Knife surgery also potential options
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- Newer, less invasive techniques include magnetic resonance imaging-guided laser interstitial thermal therapy (MRgLITT)
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# DIAGNOSTIC CHECKLIST
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- ## Consider
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- If hypothalamic mass identified in seizure imaging, think HH
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- ## Image Interpretation Pearls
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- Classic = nonenhancing hypothalamic mass
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- Isointense to gray matter on T1WI, slightly ↑ signal on T2WI/FLAIR
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- Hypothalamic astrocytoma, Langerhans cell histiocytosis (LCH), germ cell tumor all show some contrast enhancement
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1e636dc4-6e35-473c-a03d-2ed82f71d5bc
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