Intracranial germ cell tumors

Present by R3 吳孟庭

Youmans neurological surgery fifth editionChapter 231

Classsification of intracranial germ cell tumor Benign: Mature teratoma

Malignant: Germinoma (60%) Embryonal carcinoma/endodermal sinus tumor Choriocarcinoma Immature teratoma

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=2:1Male70% are found in the pineal regionFemale75% are localized to the suprasella regionIntracranial 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

Tumor type Marker profileGerminoma PLAPChoriocarcinoma HCGEmbryonal carcinoma HCG+AFPEndodermal sinus tumor AFP

Pathology- histogenesis 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.

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

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