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Intracranial germ cell tumors. Present by R 3 吳孟庭 Youmans neurological surgery fifth edition Chapter 231. Benign: Mature teratoma. Malignant: Germinoma (60%) Embryonal carcinoma/endodermal sinus tumor Choriocarcinoma Immature teratoma. Classsification of intracranial germ cell tumor.
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Intracranial germ cell tumors Present by R3 吳孟庭 Youmans neurological surgery fifth edition Chapter 231
Benign: Mature teratoma Malignant: Germinoma (60%) Embryonal carcinoma/endodermal sinus tumor Choriocarcinoma Immature teratoma Classsification of intracranial germ cell tumor
Epidemiology • Intracranial GCTs represent approximately 2-5 percent of all intracranial tumors in Japan. • GCTs (particularly germinomas) are more common in some Asian countries, where they account for 12 percent of all intracranial neoplasms. • In Western countries, the incidence is much lower, representing 0.5 percent of intracranial tumors.
Incidence Male : female=2:1 Male70% are found in the pineal region Female75% are localized to the suprasella region Intracranial GCTs peak in incidence between 10 and 14 years of age.
Clinical presentation • The presenting signs and symptoms are dependent upon tumor location. • Headache, nausea, vomiting, and lethargy (from increased intracranial pressure in patients with pineal lesions) • Diplopia, hypopituitarism or diabetes insipidus (with suprasellar tumors) • Paralysis of upward conjugate gaze (Parinaud's syndrome)
Parinaud's syndrome • known as Dorsal Midbrain Syndrome or Pretectal Syndrome • Secondary to midbrain tectal compression • It is a cluster of abnormalities of eye movements and pupil dysfunction, characterized by: 1. Paralysis of upgaze 2. Pseudo-Argyll Robertson pupils (light-near dissociation) 3. Convergence-Retraction nystagmus 4. Eyelid retraction (Collier's sign)
Image Features • Germinoma: homogeneous, isointense; may appear cystic or solid • Teratoma: heterogeneous, calcification; presence of fat
figure 231-6. A, Sagittal enhanced MRI scan of endodermal sinus tumor showing heterogeneous enhancement and cyst. B, Same patient, axial view.
Tumor marker • PLAP: placental alkaline phosphatase; HCG: human chorionic gonadotropin; AFP: alpha-fetoprotein
Primordial germ cells become disseminated widely throughout the embryo. Failure of the normal involution of these migrated totipotent cells leaves rests of cells that are susceptible to neoplastic transformation. Pathology- histogenesis
Tumor Location • Intracranial germ cell tumor arise in the midline • Pineal (50%) • Suprasella (30%) • basal ganglia, posterior fossa, pituitary gland..(10%)
Germinoma • Microscopically, irregularly sized lobules of neoplastic cells may be divided by thin connective tissue septa • Large, round neoplastic cell with a large central nucleus are intermixed with lymphocytes
Germinoma • Strong KIT expression was found in the cell membrane of germinomas. • C-kit gene mutation: common and widely distributed in intracranial germinomas Journal of Neurosurg. 2006 Mar;104(3 Suppl):173-80.
Endodermal Sinus Tumor (Yolk Sac Carcinoma) and Embryonal Carcinoma • Distinction between—unclear • Interchangeable • AFP(+)
Choriocarinoma • Rarest • An overwhelming tendency to arise in the pineal region of males. • Syncytiotrophoblasts • HCG(+)
Teratoma • Consist of tissues derived from all three germ cell layers • Mature: well-defined, cartilage, bone and hair • Immature: less well-defined and locally invasive, more central areas of hemorrhage and necrosis • Commonest tumor found in neonates
Operative management • CSF study-germ cell marker • Debulking of tumor
Postoperative management • Radiation therapy • Germinomas are exquisitely radiosensitive • Fractionated external beam irradiation • Gamma knife radiosurgery Surg Neurol. 2006 Apr;65(4):343-51
Postoperative management • Low-dose prophylactic craniospinal radiotherapy for intracranial germinoma Low-dose CSI was administered in 29 patients: usually 21 Gy of CSI, 9.0 Gy of ventricular boost, and a 19.5-Gy tumor boost, all at 1.5 Gy per fraction. Int J Radiat Oncol Biol Phys. 2006 Jun 1;65(2):481-5. Epub 2006 Mar 10
Chemotherapy • Cisplatin • VP-16 • C/T in the initial treatment of patient with nongerminomatous germ cell tumors—relative radioresistance
Survival • Germinoma-90 percent at 10 years • Nongerminomatous germ cell tumor– less than 25percent of 5-year survival rate