In 1980, Hall et all described a syndrome characterized by “hamartoblastoma”, hypopituitarism, unperfurated anus, polydactyly postaxial and numerous visceral anomalies, today known as Pallister-Hall Syndrome. On the study, Hall et all reported six cases of children with that malformation syndrome - lethal on neonatal period. None of the newborns had anterior hypophysis and the hypothalamic tumor was apparent in the inferior part of the brain, going from the optic chiasm to the interpeduncular fossa. Besides, other anomalies were found, such as: laryngeal split, abnormal pulmonary lobation, renal agenesis or dysplasia, shorts fourth metacarpals, nail dysplasia, multiple mouth frenulum, hypoadrenalism, congenital cardiomyopathy and intrauterine growth retardation. Every case was sporadic, the chromosome were apparently normal, without consaguinity relations. Several similar, milder and even asymptomatic cases were described later on. Kletter and Biesecker (1992), Topf et all (1993) and Penman Splitt et all (1994), define the disease as dominant autosomal inheritance. Kettler and Biesecker (1992) stated that most cases as sporadic as a result of a gene mutation with variable expressiveness. According to Biesecker et al (1996), an international workshop determined diagnostic criteria to the Syndrome: Hypothalamic Hamartroma and Central Polydactyly; First degree relative with hypothalamic hamartroma and polydactyly; Dominant autosomal parrent inheritance or in a consistent form with germaine mosaicism. The radiological changes are important for differential diagnosis between Pallister-Hall Syndrome and other hamartroma-present diseases. The hypothalamic hamartroma isolated has phenotypical features and causes hormonal disorders such as early puberty. On the MRI (Magnetic resonance imaging) it shows hyperintese sign on attenuated fluid. On the other hand, the Pallister-Hall Syndrome the hamartroma shows itself as a isointense signs along with other deformities as polydactyly, for example. According to Kuo et al (1999), on MRI, the classic hypothalamic hamartroma isn’t calcified, is homogenous and isointense to the grey matter on weight images in T1, and isointense and often hyperintense on weight images in T2. Those findings are pretty distinctive and help distinguish the hypothalamic hamartroma from ordinary lesions, as craniopharyngioma and hypothalamic/opticalchiasmic glioma, observed in children. Case report: The patient ALDV, male, born in 30/12/1995, was referred to evaluation on the Medical Genetic Service from HCPA. At the time, aged one year and 8 months, he was the only son of a young, healthy couple with no consanguinity. The family history of similar cases or other genetic pathologies are unknown. The prenatal happened with no intercurrences, unless the smoking mother. It was a natural birth; Birth Weight: 2kg; High: 42cm; PC: 32cm. APGAR 9. At 8 months, starts an investigation for precocious puberty, and a karyotype was performed in her hometown: 46, XY (normal). He presents convulsive crises since one year old. DNPM: cephalic support when he had 8 months, sat without support at the age of one. Physical examination: Head circumference in the 97th percentile, length above the 97th percentile. Good general condition, dysmorphic, facies with fusion of eyebrows (sinofre), epicanthus, small nose, dysplastic ears with a broad shield, three café-au-lait spots on the body. Presence of pubic hair. Increase in length and diameter of the penis, as well as of the testicles, in relation to chronological age. In the hands, significant brachydactyly with bitateral hexadactyly. In the feet, bilateral hexadactyly. Proximal cutaneous syndactyly between the 2nd and 3rd bilateral arthroids, mainly on the right. Additional exams: Rx of hands and wrists for bone age: 7 years; Chronological Age: 1 year and 10 months. Normal abdominal ultrasound; Computed Tomography of Skull/Magnetic Resonance of Skull: hypothalamic expansive lesion (3 cm), compatible with hamartoma; triventricular hydrocephalus; Cavum septum pellucidum. Endocrinological Evaluation: compatible with precocious puberty of central cause. High resolution karyotype: 46, XY (normal). Computed tomography of the brain: Examination for neurological control, performed on 10/12/2014, 18-year-old patient. It was observed solid nodular formation in the hypothalamic region, hypodense, with well-defined limits, in close contact with the mesencephalon, without impregnation by contrast medium administered intravenously, measuring about 2.9 X 2.4 X 3.0 cm, in the respective laterolateral, anteroposterior and craniocaudal planes, which in correlation with the patient’s clinical history may be related to hypothalamic Hamartoma.