Hypothalamic harmatoma (HP) is not rare, and with the common application of MRI diagnosis and the development of clinical diagnosis and treatment, more and more patients with HP have been found, and the correct diagnosis and staging can help the choice of treatment plan. I. Clinical manifestations: The common clinical manifestations of HP are neuropsychiatric symptoms and precocious puberty. The former is called class I manifestation, which is mostly manifested by twitching of hands and feet, dullness and episodic snickering; the latter is called class II manifestation, which shows signs of central precocious puberty of different degrees, including accelerated growth, early menstruation, penile enlargement and early testicular development, etc. MRI manifestations: 1. Site and size of the mass: centered on the gray nodule, adjacent to the papillae. The maximum diameter of the mass varies from 5 mm to 5 cm. When the mass is large, it may compress the papillary body; when the mass is small, it is often overlooked and missed. 2. Relationship between the mass and the third ventricular floor (gray node): (1) coronal position: the mass is mostly located in the midline of the third ventricular floor, but it may also be on one side; (2) sagittal up-and-down relationship: according to the main manifestations. It can be divided into 4 types. (1) hanging sign, the mass is suspended from the wall of the third ventricular floor by a thin tip; (2) runner sign, the mass is located within the third ventricle, creeping on the superior lateral edge of the third ventricular floor, fused with the ventricular floor and midbrain, with mild occupying effect; (3) hanging and pasting sign, similar to type 1 but different, showing a wide base of the mass immediately below the wall of the third ventricular floor, showing a change of the suprasellar pool mass, mostly between the pituitary tip and midbrain, with mild occupying effect The mass is fusiform through the base of the third ventricle and protrudes from the third ventricle and the suprasellar pool. 3, MRI signal characteristics of the mass: HP is not a true tumor, it is caused by ectopic brain gray matter, white matter and glial fibers to gray nodules, so the MRI performance on each sequence is very close to the normal brain parenchyma. Because HP has an intact blood-brain barrier, there is no enhancement on conventional enhancement scans. 4. MRS and MR-enhanced perfusion (PWI) characteristics of the mass: Although HP is rarely malignant and consists of normal brain tissue, its overall metabolic profile is different from that of normal brain gray matter and brain white matter. 1H-MRS shows that compared with normal brain gray matter, the CHO peak of HP is significantly higher, the NAA peak is slightly lower, and the CHO/NAA ratio is higher. On PWI, HP showed higher perfusion characteristics than normal gray matter. The relationship between MRI mass localization and clinical manifestations: There is an intrinsic relationship between MRI mass localization and clinical manifestations. Children with type 1 and type 3 HP tend to present with signs and symptoms of precocious puberty, while children with type 2 and type 4 HP tend to be seen for seizures. Therefore, accurate localization on MRI has important clinical value.