Teaching NeuroImages: isolated hypothalamic hamartoma vs Pallister-Hall syndrome: imaging and clinical correlation.

Antonio J. da Rocha, PhD Marcos Rosa Junior, MD Fernando Norio Arita, PhD Isolated hypothalamic hamartomas (HH) have a distinct clinical phenotype from that of PallisterHall syndrome (PHS), as HH consist of more severe seizures and cognitive, behavioral, and endocrine disorders.1 The imaging features help one to distinguish these conditions (figures 1 and 2). Isolated HH are hyperintense on fluid-attenuated inversion recovery and cause precocious puberty (PP) when they are oriented downward (parahypothalamic lesion), while seizures predominate in sessile intrahypothalamic HH.2 PHS is associated with isointense to gray matter HH, polydactyly, cutaneous syndactyly, bifid epiglottis, imperforate anus, and panhypopituitarism, resulting from GLI3 frameshift mutations (which map to chromosome 7p13) as an autosomal dominant trait.1