The pineal region is home to multiple different types of tumors, including germ cell tumors (germinoma, embryonal cell carcinoma, endodermal sinus tumors, choriocarcinoma, teratoma), astrocytomas, pineoblastoma, and pineocytomas (Figures 25-38, 25-39, 25-40, 25-41, 25-42, 25-43, 25-44, and 25-45). They make up 5% to 8% of pediatric brain tumors. The majority of germ cell tumors are germinomas (~70%).61 Pineal tumors present with signs of mass effect, including hydrocephalus, headaches, and nausea and vomiting. A classic finding is that of Parinaud syndrome, which is upgaze palsy, light-near dissociation on pupillary examination, convergence retraction nystagmus, and eyelid retraction. This is all due to compression of the superior colliculus and tectal plate.7 Germinomas may be associated with endocrinopathies, specifically diabetes insipidus primary or metastatic lesions occur in the pituitary stalk. The diagnostic workup for these lesions begins with neuroimaging. Any tumor found in the pineal region should initiate MRI with and without contrast of the entire craniospinal axis. MRI characteristics of germinoma are usually hypointense on T1 with iso- to hyperintensity on T2 and avid contrast enhancement. Non-germinomatous lesions are more likely to be irregular in shape and enhancement, and may have evidence of calcification or cyst formation.8 Blood and cerebrospinal fluid sampling for tumor markers (alpha-fetoprotein, beta-hCG, and placental alkaline phosphatase [PLAP]) are also helpful in the diagnosis of germ cell tumors. At this time, biopsy of the lesion, either endoscopically or stereotactically, can be carried out. Once a diagnosis is made, the mainstay of treatment for germinoma is chemotherapy and radiotherapy.61-64 A variety of chemotherapeutic and radiotherapeutic options are available for non-germinomatous tumors, and for non–germ-cell tumors. Surgical resection is usually reserved for those tumors that recur or are nonresponsive to medical treatment.65 Other treatment strategies designed to limit the total dose of radiation with the use of adjuvant chemotherapeutic regimens have been examined, with the goal to limit treatment-related morbidity.66,67 Overall survival for germinomas is greater than 90% at 5 years. The other tumors in this location, however, are much more difficult to control, with average survival lesser than 50% overall.
In conclusion, tumors of the pediatric CNS are relatively common, although each particular subtype is rare. The most common presenting signs and symptoms of these lesions are headache, seizure, or focal neurological deficit. Increasing head circumference or failure to meet developmental milestones are also important indications of CNS pathology. Prompt referral for neuroimaging, in most cases MRI scanning, and referral to a neurosurgeon are of paramount importance. With aggressive treatment, the majority of children with CNS neoplasms can survive into adulthood. Rates of treatment-related morbidity and long-term cognitive and developmental side effects, however, remain high. Newer therapies, imaging modalities, surgical techniques, radiation and chemotherapy, as well as molecular and genetic diagnostic methods, will likely only improve not only survival but quality of life for future patients.3,4,6,46,68