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Hypothalamic hamartoma and the Pallister-Hall syndrome
L A Squires1, S Constantini, D C Miller
1Department of Pediatrics, De Vos Children's Hospital, Michigan State University, Grand Rapids 49503, USA.
Insights
Pallister-Hall syndrome (PHS) involves hypothalamic hamartomas and extracranial abnormalities. Surgical cases reveal the maturational nature of hypothalamic lesions, challenging initial perceptions of neoplastic potential.
Area of Science:
- Neuroscience
- Developmental Biology
- Pediatric Pathology
Background:
- Pallister-Hall syndrome (PHS) was first described in 1980 as congenital hypothalamic 'hamartoblastoma' syndrome.
- Key features include hypothalamic hamartoma and extracranial abnormalities, often fatal in the perinatal period.
- Early descriptions of hypothalamic lesions suggested neoplastic potential due to primitive cell appearance.
Purpose of the Study:
- To investigate the maturational nature of hypothalamic lesions in Pallister-Hall syndrome.
- To document the phenotypic variability within the syndrome.
- To re-evaluate the initial pathological descriptions based on newer surgical cases.
Main Methods:
- Presentation of two new clinical cases of Pallister-Hall syndrome.
- Surgical removal and histopathological analysis of hypothalamic lesions.
- Comparison of histopathology with initial descriptions of PHS.
Main Results:
- Surgically removed hypothalamic lesions from older children showed a mature hamartoma histology.
- Findings contradict the initial interpretation of neoplastic potential in perinatal PHS cases.
- The two presented cases illustrate the syndrome's phenotypic variability.
Conclusions:
- Hypothalamic lesions in Pallister-Hall syndrome exhibit maturational potential, evolving from primitive-appearing cells to typical hamartomas.
- The syndrome's presentation is variable, and early descriptions may have overemphasized neoplastic potential.
- Further study of PHS pathogenesis and long-term outcomes is warranted.
Abstract:
The Pallister-Hall syndrome (PHS) was initially described as the congenital hypothalamic 'hamartoblastoma' syndrome in 1980. Cardinal manifestations of the syndrome consist of a hypothalamic hamartoma and extracranial abnormalities, initially thought to be fatal in the perinatal period. The original pathologic description of these hypothalamic lesions were from infants who died in the perinatal period and revealed small cells of variable density which resembled primitive undifferentiated germinal cells and appeared to invade the hypothalamic nuclei, suggesting a neoplastic potential. Hypothalamic lesions have now been removed from older infants and children with this syndrome and reveal a more mature histologic appearance typical of a hypothalamic hamartoma. We present 2 new cases of PHS who underwent surgery and demonstrate the maturational nature of the hypothalamic lesion and the phenotypic variability of the syndrome.