Tumors that occur in the parenchymal cells of the pineal gland include pineal cell tumors and pinealoblastomas. The majority of what used to be called pineal tumors are germ cell tumors or atypical teratomas, while true pineal cell tumors are rare. There is a wide age range, with pineal cell tumors being more common in adults and pinealoblastomas in children. The rates are approximately equal between the sexes.
Clinical manifestations
1.Increased intracranial pressure
The tumor may develop into the posterior part of the third ventricle and obstruct the superior port of the aqueduct, or the aqueduct may become narrowed or atretic, resulting in early onset of obstructive hydrocephalus and clinical manifestations of increased intracranial pressure, such as headache, vomiting, fundus edema and altered state of consciousness.
2.Neurological symptoms
(1) Ophthalmic signs: tumor compression on the superior colliculus of the tetrahymena may cause upward and downward eye movement disorder, pupil dilatation or unequal size, etc.
(2) Hearing impairment: If the tumor is large, it may compress the inferior colliculus of the tetrahymena and the medial geniculate body and cause bilateral tinnitus and hearing loss.
(3) Cerebellar sign: The tumor may compress the superior peduncle and superior cerebellar area, so trunk ataxia and nystagmus may appear.
(4) Subthalamic damage: It may be caused by the direct invasion of the tumor or disseminated planting to the subthalamic region, or the tumor may cause the obstruction of the aqueduct and the expansion of the anterior part of the third ventricle and affect the subthalamic region.
3.Endocrine symptoms
The normal pineal gland can secrete melatonin, which can inhibit the function of pituitary gland and reduce the content and secretion of gonadotropin in pituitary gland. Therefore, the delayed development of sexual characteristics is seen in pineal tumor patients with pineal cell tumor.
4.Other symptoms
Due to the increased intracranial pressure and direct compression of the midbrain by the tumor, some patients may experience seizures, pathological reflexes and even impaired consciousness. The spinal cord can cause damage to the spinal cord and cauda equina, resulting in neuralgia or sensory impairment.
Auxiliary examinations
1.CT examination
The tumor may appear as low density, isometric mixed density or homogeneous slightly high density foci, and the tumor may appear as well-defined round-like foci, there may be scattered small calcification foci, bilateral lateral ventricles and the anterior part of the third ventricle are enlarged, if there is ventricular canal or subventricular metastasis, the band around the lateral ventricles and the third ventricle on both sides is slightly high density foci, and there may be uniform and consistent contrast enhancement.
2.MRI examination
MRI examination shows isosignal or low signal in T1-weighted image and high signal in T2-weighted image. Sagittal scan is helpful to understand the growth direction of tumor and the degree of midbrain compression.
Treatment and Prognosis
The treatment of pineal cell tumor should be mainly surgical, because the tumor is not very sensitive to radiation therapy due to its pathological nature, and in some patients, although the intracranial pressure is not high after ventricular shunt, the signs of midbrain compression are more obvious. According to the direction of tumor development, different surgical approaches should be used, mainly the trans-Poppen approach and the intercallosal vault approach. For those whose tumors are not completely resected and the cerebrospinal fluid circulation obstruction is not released, the lateral ventriculoperitoneal shunt should be performed in time.