Increased ICP due to hydrocephalus
The clinical signs and symptoms of pineal region tumors are most often due to increased ICP related to obstructive hydrocephalus at the Aqueduct of Sylvius.
- Headaches: Patients most commonly present with intermittent headache increasing in severity and duration over time. Headaches are typically worst in the morning and may awaken the patient from sleep.
- Nausea and vomiting: Nausea and emesis may be present.
- Diplopia: Blurry or double vision may develop due to abducens palsy, papilledema, or compression of the tectal plate.
- Ataxia: Ataxia may occur when advanced hydrocephalus is present.
- Altered mental status: In cases of severe, progressive hydrocephalus, patients may develop altered mental status.
- Visual: Pineal region tumors can cause a classic picture of Parinaud’s syndrome, consisting of upgaze palsy, light-near dissociation (Pseudo Argyll Robertson pupil), convergence-retraction nystagmus (nystagmus retractorius), and lid retraction (Collier’s sign). Increased intracranial pressure can cause papilledema and blurry vision. Patients with simultaneous suprasellar and pineal germ cell tumor may demonstrate visual impairment and hormonal dysfunction including diabetes insipidus. Pineoblastomas and germinomas may also disseminate in the subarachnoid space of the craniospinal axis, causing signs due to optic nerve or spinal cord compression.
- Hormonal: Precocious puberty is rare but may occur in males with choriocarcinoma due to increased testicular androgen secretion stimulated by β-HCG expressed by tumor cells. Precocious puberty may also be diagnosed in cases of teratoma and mixed germ cell tumors.
Pattern of evolution
- Usually evolving hydrocephalus symptoms: The pattern of symptoms due to pineal region tumors depends on the location and rate of lesion growth. Slow-growing lesions will remain asymptomatic until large enough to cause obstructive hydrocephalus or compression of nearby structures, including the tectal plate. In general, symptoms secondary to obstructive hydrocephalus are the first to emerge, followed by ocular and cranial nerve deficits. Small lesions in the pineal region such as pineal cysts and astrocytomas of the quadrigeminal plate may remain asymptomatic and be found incidentally.
Time for evolution
- Varies with growth rate of tumor: The timing of symptom evolution depends on tumor histology and the rate of tumor growth. Benign masses such as pineal cysts or pineocytomas may be slow growing, causing subtle signs of intermittent obstructive hydrocephalus over time. Astrocytic tumors of the pineal region are most often low grade and usually demonstrate only indolent progression. In contrast, fast-growing lesions such as pineoblastomas and germinomas may have rapid onset and progression of symptoms, prompting cranial imaging and lesion diagnosis. Acute symptoms of compression or altered mental status may also occur due to secondary hemorrhage into the tumor mass (pineal apoplexy) or the subarachnoid space.
Preparation for definitive intervention, nonemergent
Children and adolescents with pineal region tumors and negative tumor markers require surgical biopsy for diagnosis.
- Assessment of presentation, imaging, and markers for diagnosis: Neuroimaging studies often enable differentiation of pineal teratomas from other tumors due to their distinct and characteristic radiographic appearance. Neuroimaging studies may also be diagnostic for pineal germinomas in teenage males with negative tumor markers. Patients with germinomas or NGGCTs may also have an elevated serum β-HCG level, in which case chemotherapy may also be recommended, in addition to radiation therapy, without surgical biopsy. Solid double tumors in the anterior and posterior third ventricle are considered a malignant germ cell tumor (germinoma or NGGCT) requiring chemotherapy followed by radiation, and may be diagnosed without tissue biopsy. Infants and preschool-age children are rarely diagnosed with germ cell tumors. In these patients the most common tumor of the pineal region is pineoblastoma, and therefore craniotomy for tumor resection is advised.
- Stabilization of elevated ICP: Patients with obstructive hydrocephalus will require a CSF diversion procedure. CSF diversion may be performed prior to definitive tumor management or concurrent with surgical biopsy or resection when applicable. It may be achieved via EVD placement, ETV, or placement of a ventriculoperitoneal shunt. Considerations when planning for a CSF diversion procedure include the extent of hydrocephalus, patient anatomy, tumor histology, and planned operative approach for tumor biopsy or resection. In cases where tumor resection is not planned, an ETV may be needed to divert CSF flow until the tumor mass is reduced with radiation or chemotherapy. Ventriculoperitoneal shunt placement may put the patient at risk for peritoneal seeding, particularly in patients with germinomas and pineoblastomas. In these cases, ETV is preferable.
- Planned CSF sampling needs: Ommaya reservoir placement for serial CSF studies to monitor treatment response is also advised.
Preparation for definitive intervention, emergent
- Treatment of elevated ICP: Patients may experience altered mental status or respiratory compromise due to severe or acutely progressive hydrocephalus, tumor mass effect, or acute hemorrhage (pineal apoplexy). In these cases, patients may require intubation to protect their airway and emergent surgical CSF diversion. Emergent EVD placement at the bedside can be performed in extreme situations; however it is preferable to perform CSF diversion in the operating room whenever possible. If the patient’s anatomy is favorable, ETV and Ommaya valve placement may be performed, a procedure preferred to ventriculoperitoneal shunt placement. In patients where ETV is not possible, an EVD may be placed. In cases of pineal apoplexy, emergent hematoma evacuation and tumor debulking may be necessary.
- Laboratory studies: Serum β-HCG and AFP levels should be included in admission laboratory work. CSF should be obtained for CSF cytology, β-HCG, and AFP in addition to routine studies.
- Imaging: Imaging should include MRI of the brain with and without gadolinium enhancement. If the study is to be used for neuronavigation, the appropriate fiducial markers should be placed and imaging set obtained for use with the intraoperative stereotactic guidance system.
- Imaging for tumor staging: MRI of the spine with and without gadolinium enhancement should be obtained for tumor staging.
- EVD drainage: If an EVD is present, it should be opened to drain to a pressure of 10 cm of water.
- Dexamethasone: All of our children receive 4 mg PO every 6 hours.