CNS & pituitary tumors
Germ cell tumors
Germ cell tumors
Author: Nat Pernick, M.D.
Last author update: 1 January 2006
Last staff update: 15 January 2024
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Germinoma CNS
Cite this page: Pernick N. Germ cell tumors. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumorgermcelltumors.html. Accessed April 23rd, 2024.
Choriocarcinoma
Definition / general
Case reports
Microscopic (histologic) description
Positive stains
Differential diagnosis
- Prognosis poorer than germinoma - median survival 22 months in cases with high hCG levels (J Neurooncol 2004;66:225)
- Serum levels of hCG are helpful
Case reports
- 1 month old infant with intracranial choriocarcinoma (Arch Pathol Lab Med 1990;114:1079)
- 8 year old boy with intracranial choriocarcinoma causing precocious puberty and cured with combined modality therapy (J Paediatr Child Health 1993;29:464)
Microscopic (histologic) description
- Syncytiotrophoblasts (large multinucleated cells) and cytotrophoblasts
Positive stains
Differential diagnosis
- Metastatic choriocarcinoma:
- From gonads or placenta
Embryonal carcinoma
Definition / general
Treatment
Positive stains
- Prognosis poorer than germinoma
- May be associated with precocious puberty
- Characterized by rapid and bulky growth and spread to liver and lungs
- 60% have metastases at presentation
Treatment
- Chemotherapy
- Radiation therapy
- Surgery
Positive stains
Germinoma
Definition / general
Staging / staging classifications
Case reports
Treatment
Gross description
Microscopic (histologic) description
Cytology description
Positive stains
Negative stains
Electron microscopy description
Differential diagnosis
Additional references
- Most common intracranial germ cell neoplasm
- Often teenagers and young adults
- Two - thirds male
- May be mixed with other germ cell tumors
- May derive from ectopic rests, transformation of resident germ cells or migration of germ cells late in development
- Most common site is pineal region
- Also anterior or posterior third ventricle, rarely fourth ventricle
- Rarely associated with dysgenetic syndromes
- Immunostains useful because biopsy is often small
- Relatively good prognosis (5 - 10 year survival is 75 - 95%) versus 25 - 40% for nongerminoma germ cell tumors (Pediatr Neurol 2002;26:369)
- Very sensitive to radiotherapy and chemotherapy; nongerminomatous germ cell tumors are less radiosensitive
- Metastases may be due to surgical displacement of tumor
- Spinal cord metastases occur in 10 - 15% of patients
Staging / staging classifications
- T1: smaller than 5 cm in diameter and located in the suprasellar, intrasellar or pineal region
- T2: larger than 5 cm in diameter and located in the perisellar region
- T3: may be smaller than 5 cm in diameter but invades and encroaches on the third ventricle
- T4: extends into the anterior, middle or posterior fossa
- N: not indicated for CNS tumors
- M0: no evidence of gross subarachnoid or hematogenous metastasis
- M1: microscopic tumor cells found in the CSF
- M2: gross nodular seeding in the ventricular system or cranial subarachnoid spaces
- M3: gross nodular seeding in the spinal subarachnoid spaces
- M4: metastasis outside the cerebrospinal axis
Case reports
- 23 year old man with headaches and visual difficulties (Arch Pathol Lab Med 2003;127:497)
Treatment
- Resection difficult due to high collagen content
- Radiation therapy helpful
Gross description
- Soft, gray-pink, homogenous
- Variable encapsulation
- Usually poorly circumscribed and infiltrative
Microscopic (histologic) description
- Resembles seminoma / dysgerminoma
- Large, epithelioid cells with abundant PAS+ cytoplasm, large, round nuclei and irregular and pleomorphic nuclei
- May have prominent nests of lymphocytes with occasional granulomatous inflammation that may obscure tumor cells (Neurol Med Chir (Tokyo) 2005;45:415)
- Lymphocytes may smear in small biopsies
- Frequent mitotic activity and necrosis
- Syncytiotrophoblasts in 14%
- Less anaplasia than embryonal carcinoma
- No cells intermediate in size between lymphocytes and large germinoma cells
Cytology description
- Loose fragments or single large pleomorphic and polygonal cells with vacuolated cytoplasm, enlarged oval nuclei and prominent nucleoli
- Frequent mitotic figures, naked nuclei, foamy background
- Also smashed lymphoid cells with streaking
Positive stains
- PLAP, PAS+ cytoplasm, CD117 / c-kit, OCT4 (strong, often diffuse)
Negative stains
Electron microscopy description
- Glycogen in cytoplasm, sparse cytoskeletal elements, prominent nucleoli
Differential diagnosis
- Carcinoma:
- Usually metastatic, keratin+, EMA+, 13% are PLAP+
- Embryonal carcinoma:
- 25% are PLAP+
Additional references
Teratoma
Definition / general
Terminology
Prognostic factors
Case reports
Treatment
Additional references
- Tissue derived from ectoderm, endoderm and mesoderm (at least 2 of 3 germinal layers)
- Usually well differentiated / grade I of IV
- Incidence varies with age: 30 - 50% of congenital brain tumors, 2% of brain tumors in infants and children, 0.5% at all ages
- Congenital cases are usually fatal; may replace cerebral hemispheres (Pediatr Pathol 1987;7:333)
- Mature teratomas:
- Have well differentiated tissue from all three germinal layers, including neuroectoderm, epithelium (solid, cystic, glandular or tubular), cartilage or other mesenchymal elements, glial and neuronal tissue
- Immature teratomas:
- Have less differentiated tissue from any of the three germinal layers
- 50% with intracranial tumors die within one year
- Pineal teratomas are more common in males but saccrococcygeal teratomas are more common in females
- Must sample thoroughly for correct diagnosis
Terminology
- Growing teratoma syndrome
- Enlarging teratoma after tumor treatment (Neurosurgery 2005;56:188)
Prognostic factors
- Poor prognostic factors: tissue resembling medulloepithelioma, neuroblastoma, retinoblastoma or ependymoblastoma
Case reports
- 27 week old fetus with massive macrocephaly and generalized anasarca (Arch Pathol Lab Med 2004;128:102)
- Congenital intracranial teratoma of the lateral ventricle (Neurol India 2001;49:170)
- 3 day old girl with congenital intracranial immature teratoma of the lateral ventricle (Neurol Res 2005;27:53)
Treatment
- Newborns: complete surgical excision (difficult)
Additional references
Yolk sac tumor
Definition / general
Case reports
Gross description
Microscopic (histologic) description
Positive stains
Additional references
- Rare intracranial tumor, usually in pineal or suprasellar regions
- Also called endodermal sinus tumor
- Prognosis poorer than germinoma (median survival 2 years or less)
Case reports
- 15 year old girl with an unusual presentation of an intraparenchymatous frontal yolk sac tumor (Neurol India 2001;49:395)
- 22 year old man with Down syndrome and pineal yolk sac tumor with a solid pattern (J Clin Pathol 2004;57:882)
Gross description
- Usually large
Microscopic (histologic) description
- Tubulopapillary structures with vacuolated cuboidal cells, cystic spaces with eosinophilic hyaline bodies and Schiller-Duval bodies
Positive stains
Additional references
