There are various pathological types of pineal region tumors and different treatment modalities, mainly including neuroendoscopic triple ventricular floor fistula and tumor biopsy, craniotomy, stereotactic biopsy, ventriculo-abdominal shunt and radiotherapy. Due to the deep location of the pineal region and complex surrounding structures, the surgical risk is high, and no consensus has been reached on the treatment strategy for tumors in the pineal region. Data and methods 1. General data: Among the 42 patients in this group, 35 were male and 15 were female, male:female=7:3. Age ranged from 1 to 52 years old, with an average of 26,9 years old. The duration of the disease was 10 days to 3 years, with an average of 2, 5 months. Clinical symptoms mainly included headache, dizziness and nausea and vomiting in 36 cases; blurred vision, diplopia and eye movement disorders in 10 cases; unstable walking in 6 cases; and seizure in 1 case. All patients underwent cranial CT and MRI scans before surgery, and were found to have round or round-like occupying lesions in the pineal region, which could have different manifestations of cystic, solid or cystic solidity, some of which could be seen as calcification, and most of the tumors could be enhanced with different degrees of obstructive hydrocephalus, and no occupying lesions were found outside the pineal region (Figure 1a, 1b). And preoperatively, the cranial MRI 3D proton-weighted fast spin-echo sequence, Harvard University, USA) was post-processed and virtual endoscopic imaging was performed to clarify the occupying surrounding tissue in the pineal region (Figure 2a, 2b) for accurate preoperative assessment. 3. Tumor marker test data: 50 patients were tested for serum and cerebrospinal fluid tumor markers of alpha-fetoprotein (AFP), chorionic gonadotropin (HCG), and carcinoembryonic antigen (CEA) preoperatively; 5 cases had elevated HCG alone; 2 cases had elevated AFP alone; 2 cases had elevated both HCG and AFP. Results 1. Treatment procedures: (1) Ventriculoscopic treatment group: 35 patients underwent triple ventriculostomy + tumor biopsy or tumor resection with the assistance of ventriculoscopy, and soft fiber neuroendoscopy was applied to perform midbrain catheteroplasty in 3 cases, and the postoperative pathological examination results were teratoma and ventricular meningioma, which were then removed by craniotomy. (2) Craniotomy treatment group: including 13 cases of parieto-occipital craniotomy with suboccipital superior cerebellar curtain approach (Poppen approach), 7 cases of transversal longitudinal fissure right ventricular choroidal fissure approach, 2 cases of transverse subcurtain superior cerebellar approach, and 1 case of transverse posterior longitudinal fissure approach. (3) After surgery, further pharmacological chemotherapy (cisplatin, etoposide, bleomycin, i.e., PEB regimen) and radiotherapy were administered according to the pathological findings, and imaging and serum tumor markers were reviewed regularly. The treatment process is detailed in the following flow chart. Pathological results: The postoperative pathological results suggested 23 cases of germ cell tumor, 4 cases of teratoma, 7 cases of meningioma, 2 cases of ventricular meningioma, 5 cases of astrocytoma, 4 cases of pineal cell tumor, 4 cases of pineoblastoma, and 1 case of pineal papilloma. 3. The diagnosis rate was 100%; most of the patients’ cranial hypertension symptoms were relieved or disappeared within 1 week after the operation, and the cranial MRI showed that the base of the three ventricles was flattened, and the cerebrospinal fluid flow was visible in the fistula and midbrain conduit, and the hydrocephalus was reduced or disappeared. 1 case underwent further ventriculotomy for external drainage due to delayed ventricular hemorrhage. After the histopathological findings of the tumor were returned, further pharmacological chemotherapy (cisplatin, etoposide, bleomycin, i.e., PEB regimen) and radiation therapy were formulated. (2) Craniotomy group: 23 cases were treated by craniotomy, and 21 cases had complete resection of the tumor, with a complete resection rate of 91,3% and 2 cases had sub-total resection. Among them, 2 patients had delayed intracranial hemorrhage and underwent craniotomy again to remove the hematoma; 2 patients had postoperative obstructive hydrocephalus and underwent further ventriculoscopy-assisted triple ventriculostomy; 6 patients had different degrees of isotropic hemianopia, all of them recovered within 2 weeks. 4. Follow-up: Regular postoperative follow-up and imaging and serum tumor marker review were performed at 1 month, 3 months, 6 months and annually thereafter, with a mean follow-up time of 2 and 7 years. Most of the tumors showed basic disappearance of the tumors by cranial MRI (Figure 5a and 5b) after 3 months, and there were no obvious signs of recurrence of tumors and hydrocephalus. One case in the ventriculoscopic treatment group underwent further ventriculoperineal drainage due to late ventricular bleeding, and the postoperative intracranial infection with a complication rate of 3,7%. In the craniotomy group, 2 cases were reoperated due to late bleeding, and there was postoperative impaired consciousness and intracranial infection, with a complication rate of 8,7%. Discussion Tumors of the pineal region are occupying lesions located in the pineal region with various pathological types, mainly including germ cell tumors, pineal parenchymal cell tumors, glial cell tumors and other types of cell tumors and cysts. Within each of these categories, there are both benign and malignant tumors, and there can be mixed types of tumors composed of more than one type of cell. Other types of tumors include meningiomas, hemangioblastomas, choroid plexus papillomas, metastases, adenocarcinomas, and lymphomas. There are also vascular lesions such as cavernous hemangiomas, metastases, arteriovenous malformations, and Galen’s venous malformation. The pineal region is deeply located with complex surrounding structures, dorsal to the corpus callosum pressure, anterior to the posterior border of the three ventricles, posterior to the superior cerebellar earthworm, and ventral to the midbrain parietal and tetrahymenal plates. Therefore, pineal tumor can cause cranial hypertension symptoms, such as headache, vomiting and secondary optic nerve atrophy and blurred vision due to optic papilloedema, due to obstructive hydrocephalus caused by compression of middle cerebral aqueduct at early stage. As the tumor grows, it may compress the superior colliculus of the tegmentum in the dorsal cap of the midbrain, resulting in vertical eye movement disorder (Parinaud syndrome). In advanced stages, compression of the inferior colliculus of the tegmentum leads to hearing loss, compression of the superior cerebellar earthworm or the superior cerebellar peduncle, resulting in unstable walking and other symptoms. A few patients with germ cell tumors may have endocrine symptoms such as precocious puberty and enuresis due to the nature of the tumor (teratoma or choriocarcinoma) or tumor invasion of the pituitary stalk. The diagnosis of pineal tumor is mainly based on clinical symptoms, cranial CT and MRI examinations, as well as serum and cerebrospinal fluid tumor markers and cytological examinations, but the “gold standard” for diagnosis is still tumor histopathological biopsy. However, there are some difficulties in neuroendoscopic treatment of pineal tumor: ①The location of the fistula is located in the anterior part of the third ventricle, while the location of tumor biopsy is in the posterior part of the third ventricle, so the endoscopic angle changes too much, which may cause damage to the thalamic vein, septal vein, bleeding and damage to the fornix and interthalamic union. ②Compared with microscopic surgery, a small amount of intraoperative bleeding seriously affects the operating field, and the problem of hemostasis under neuroendoscopy is still difficult. ③For some mixed tumors, neuroendoscopic biopsy may sometimes affect the pathological diagnosis and the next treatment plan due to the small number of sampling sites and insufficient specimen volume. In conclusion, for pineal tumors, neuroendoscopic triple ventriculostomy + tumor biopsy (or tumor resection) not only causes less injury and complications, but also rapidly solves the problem of obstructive hydrocephalus and relieves clinical symptoms, and provides pathological diagnostic support for further treatment planning by performing tissue biopsy to clarify the nature of the tumor, which can be the preferred treatment for some pineal tumors, especially for patients with combined obstructive hydrocephalus. It can be the treatment of choice for some patients with pineal tumors, especially those with combined obstructive hydrocephalus.