You are in: eMedicine Specialties > Radiology > BRAIN/SPINE Pineal GerminomaArticle Last Updated: Apr 18, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Chi-Shing Zee, MD, Chief of Neuroradiology, Professor, Departments of Radiology and Neurosurgery, University of Southern California School of Medicine Chi-Shing Zee is a member of the following medical societies: American Society of Neuroradiology Coauthor(s): Paul Kim, MD, Assistant Professor of Radiology, USC School of Medicine; Vi Vu, MD, Clinical Instructor, USC School of Medicine Editors: Pamela W Schaefer, MD, Assistant Professor of Radiology, Harvard Medical School; Associate Director of Neuroradiology, Clinical Director of Magnetic Resonance Imaging, Department of Radiology, Massachusetts General Hospital; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; James G Smirniotopoulos, MD, Professor of Radiology, Neurology, and Biomedical Informatics, Chairman, Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences Author and Editor Disclosure Synonyms and related keywords: pineal gland, pineal region neoplasms, germ cell tumors, pineal cell tumors, germinoma, mature teratoma, malignant teratoma, embryonal cell carcinoma, endodermal sinus tumor, choriocarcinoma, mixed germ cell tumor, parapineal masses, thalamic quadrigeminal plate and tectum, glioma, ependyma, ependymoma, velum interpositum and tentorium, meningioma, Parinaud syndrome INTRODUCTIONSection 2 of 9
  BackgroundAlthough pineal region neoplasms constitute only 0.3-2.7% of intracranial tumors, they are considered an important clinical entity because of their strategic location. Pineal region neoplasms can be classified into 3 major groups according to their cellular origin: (1) tumors of germ cell origin, (2) tumors of pineal cell origin, and (3) tumors of other cell origin. Tumors of germ cell origin include germinoma, mature teratoma, malignant teratoma, embryonal cell carcinoma, endodermal sinus tumor, choriocarcinoma, and mixed germ cell tumors. In addition, pineal germinomas and suprasellar germinomas are associated. Pineal germinomas are seen predominantly in males aged 0-20 years. PathophysiologyHerophilus discovered the pineal gland in 300 BC, and Galen labeled the gland konareion, meaning shaped like a pinecone. From a physiologic perspective, the pineal gland is centrally situated to serve as the center of a system of input, feedback, and regulation among diverse areas in the brain. Human physiologic systems evolve cyclically, with an internal awareness of diurnal and seasonal cycles. The pineal gland is responsible for both clock and calendar information. Through the production and release of numerous neurohormonal substances, the pineal gland integrates the signals it receives from the environment. Of the various substances produced by the pineal gland, melatonin is the most important. The control of melatonin synthesis by light makes the photoperiodicity of the pineal gland possible. Many types of neoplasms can arise from the pineal region owing to the presence of various histologically unrelated tissues. Neoplasms include those of the pineal gland (eg, germ cell tumors, pineal cell tumors); thalamic quadrigeminal plate and tectum (eg, glioma); ependyma (eg, ependymoma); and velum interpositum and tentorium (eg, meningioma). Metastasis and vascular lesions have also been reported. The most common pineal tumors are germinomas. Germinomas are most commonly seen in the pineal region, followed by the suprasellar region. Occasionally, they may be seen in the thalamus or basal ganglia. The cellular origin of germinoma usually is ascribed to primitive germ cells that are believed to migrate over wide areas of the embryo during early fetal life. Other germ cell tumors include embryonal cell carcinoma, endodermal sinus carcinoma, choriocarcinoma, and mixed germ cell tumor; however, these are much less common than germinomas. The marker profile in cerebrospinal fluid or serum may be helpful in the differential diagnosis of germ cell tumors in the pineal region. Choriocarcinoma produces human chorionic gonadotropin, endodermal sinus tumor produces alpha fetoprotein, and embryonal cell carcinoma produces alpha fetoprotein and human chorionic gonadotropin. Mixed germ cell tumors may produce a combination of these tumor markers. FrequencyUnited StatesPineal region neoplasms constitute 0.3-2.7% of all intracranial tumors. Germinoma is the most common pineal region neoplasm, constituting approximately 40% of cases. Pineal germinomas occur more frequently in males and are more common than suprasellar germinomas. InternationalA high incidence of pineal germinoma is found in Japan. Mortality/Morbidity
RaceThe incidence of pineal region neoplasms is high in Japanese individuals. Sex
AgeGerminomas appear in persons aged 0-20 years. AnatomyThe pineal gland is situated deep in the brain near critical neural and vascular structures. This position accounts for the neurologic symptoms that may occur when a mass lesion arises in the pineal gland. The pineal gland is located in the most posterior portion of the roof of the third ventricle. The posterior commissure is posterior and inferior to the pineal gland. Anterior to the pineal gland are the habenular trigone and the striae medullaris thalami. The splenium of the corpus callosum is situated above the pineal gland. The pineal gland is located in the pineal recess of the third ventricle and surrounded by a pial layer. The substances produced by the pineal gland are released into the vascular system. Through numerous perforators, the medial posterior choroidal arteries are the major feeders of the gland. A large venous outflow proceeds through the internal cerebral veins and the vein of Galen and contributes to the distribution of substances synthesized in the pineal gland. Clinical DetailsParinaud syndrome, a condition secondary to compression of the tectum, is the most important clinical presentation of pineal germinomas. The triad of Parinaud syndrome includes palsy of the upward gaze, dissociation of light and accommodation, and failure of convergence. In addition, findings secondary to hydrocephalus resulting from aqueductal compression are seen. Pineal germinomas may be associated with precocious puberty in male patients. Preferred ExaminationMRI is the preferred imaging modality. MRI enables the accurate delineation of pineal masses before surgery. MRI allows true pineal masses to be distinguished from parapineal masses that impinge on the pineal gland. Limitations of TechniquesMRI is not perfect in the detection of calcifications. CT may be needed to evaluate a calcified pineal gland that is associated with a pineal germinoma or tumor calcification associated with other neoplasms in the pineal region. DIFFERENTIALSSection 3 of 9
Astrocytoma, Brain Ganglioglioma Meningioma, Brain Other Problems to Be ConsideredOther pineal germ cell tumors
RADIOGRAPHSection 4 of 9
FindingsGerminomas are associated with a high incidence of pineal gland calcification. The tumor does not calcify, but it may engulf a calcified pineal gland. A calcified pineal gland is rarely seen on radiographs in a child younger than 10 years. If a calcified pineal gland is seen on plain radiographs in a boy younger than 10 years, pineal germinoma is suggested. Degree of ConfidenceThe degree of confidence with radiographs is low. A calcified pineal gland in young male patients is suggestive of germinoma, but a normal pineal gland can also become calcified. In patients younger than 10 years, physiologic calcification of a healthy pineal gland is usually not detectable on plain radiographs. Furthermore, pineal calcification can be seen in patients with pineal cell tumors. CT SCANSection 5 of 9
FindingsNonenhanced CT scans typically demonstrate a slightly hyperattenuating mass that engulfs a prominent calcified pineal gland. Contrast-enhanced CT demonstrates homogeneous and intense enhancement. CT is more sensitive than plain radiography in depicting pineal calcification. Small speckles of calcification can be seen in children as young as 6 years. In general, pineal calcification in children younger than 6 years is suggestive of pineal neoplasm. Other authors believe that pineal calcification is uncommon in children younger than 10 years and that areas of pineal calcification should be smaller than 1 cm in diameter. Degree of ConfidenceThe degree of confidence is moderate with CT. MRISection 6 of 9
FindingsGerminomas are usually relative to cerebral gray matter on both T1-weighted images and T2-weighted images. Occasionally, tumors may be hypointense on T1-weighted images and hyperintense on T2-weighted images. After the intravenous injection of gadolinium-based contrast material, homogeneous and intense enhancement is seen. For this reason, contrast-enhanced MRI is particularly useful for evaluating the subarachnoid seeding of germinomas. Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. As of late December 2006, the FDA had received reports of 90 such cases. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble movingor straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape. Pineal germinomas predominantly involve the pineal gland, but involvement of the medial aspect of the pulvinar of the thalamus frequently is seen. Occasionally, small cystic changes may be seen in the germinoma. A recent study demonstrated that the tumoral response to radiation therapy is negatively correlated with the presence of cystic changes in the germinoma. Degree of ConfidenceThe degree of confidence is high within MRI. MRI enables the accurate anatomic delineation of the tumoral mass and the determination of its relationship with the surrounding structures. Thus, MRI can provide adequate information with which the neurosurgeon can plan a biopsy. ANGIOGRAPHYSection 7 of 9
FindingsNo abnormality is seen on arterial-phase cerebral angiograms. In the venous phase, superior and posterior displacement of the internal cerebral veins and the vein of Galen may be seen on lateral projections. A larger pineal region mass can cause posterior bowing of the precentral cerebellar vein. On anteroposterior projections, the posterior portion of the 2 internal cerebral veins may be slightly separated. Degree of ConfidenceVenous-phase cerebral angiograms can help in identifying a pineal region mass, but a more specific diagnosis is not possible. MULTIMEDIASection 8 of 9
REFERENCESSection 9 of 9
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