Skip to content

Non-Germinomatous Germ Cell Tumour

Summary

fleuron

  • Rare intracranial neoplasms arising from primordial germ cells
  • Heterogeneous group including teratomas, embryonal carcinomas, yolk sac tumours, and choriocarcinomas
  • Typically present with mass effect symptoms and have variable imaging appearances

Pathophysiology

  • Arise from primordial germ cells that fail to migrate properly during embryogenesis
  • Classified based on histological components:
    • Teratoma: contains tissue from all three germ layers
    • Embryonal carcinoma: undifferentiated cells resembling embryonic stem cells
    • Yolk sac tumour: endodermal sinus-like structures
    • Choriocarcinoma: trophoblastic differentiation
  • Often mixed tumours with multiple histological components

Demographics

  • Rare, accounting for <5% of all primary intracranial tumours
  • Peak incidence in adolescents and young adults (10-21 years)
  • Male predominance (M:F ratio 2-3:1)
  • Most common locations:
    • Pineal region
    • Suprasellar region
    • Basal ganglia/thalamus

Diagnosis

  • Clinical presentation:
    • Mass effect symptoms (headache, nausea, vomiting)
    • Visual disturbances (if suprasellar)
    • Endocrine dysfunction
    • Precocious puberty (in some cases)
  • Tumour markers:
    • Alpha-fetoprotein (AFP)
    • Beta-human chorionic gonadotropin (β-hCG)
    • Placental alkaline phosphatase (PLAP)
  • Cerebrospinal fluid (CSF) cytology for staging

Imaging

  • CT:
    • Heterogeneous mass with variable enhancement
    • Calcifications common in teratomas
  • MRI:
    • T1: Variable signal intensity
    • T2: Heterogeneous, often hyperintense
    • T1 post-contrast: Heterogeneous enhancement
    • DWI: Variable restriction
    • Susceptibility-weighted imaging (SWI): May show haemorrhage or calcifications
  • Specific features:
    • Teratoma: Fat-containing components, calcifications
    • Embryonal carcinoma: Large, heterogeneous masses with necrosis and haemorrhage
    • Yolk sac tumour: Cystic components, haemorrhage
    • Choriocarcinoma: Haemorrhagic mass

panels-1

  • A 25-year-old patient presented with headache, lethargy, and various neurological deficits.
  • CT showed hydrocephalus secondary to a large hyperdense solid-cystic lesion.
  • The lesion was enhancing and contained fluid-fluid levels and petechial haemorrhage based on SWI (not shown). The lesion extended along the ependyma and involved the infundibulum.
  • The final diagnosis was a non-germinomatous germ cell tumour.

Treatment

  • Multimodal approach:
    • Surgery: Maximal safe resection
    • Chemotherapy: Platinum-based regimens (e.g., cisplatin, etoposide)
    • Radiotherapy: Craniospinal irradiation for disseminated disease
  • Risk-adapted treatment based on histology and tumour markers
  • Regular follow-up imaging and tumour marker monitoring
  • Overall prognosis poorer than germinomas, but varies by histological subtype

Differential diagnosis

Differential Diagnosis Differentiating Feature
Germinoma Typically has a more homogeneous appearance on imaging; better prognosis
Pineoblastoma Usually occurs in younger patients; more aggressive behaviour
Ependymoma Tends to have a more well-defined margin; often enhances more uniformly
Choroid plexus papilloma Usually located within ventricles; tends to be more vascular
Craniopharyngioma Often contains calcifications; cystic components more common
Metastasis Multiple lesions at grey-white junction; no pineal or suprasellar predilection; no fat or calcification
Lymphoma Tends to be more homogeneous; often shows restricted diffusion on MRI
Teratoma May contain fat, calcifications, or teeth; more heterogeneous appearance
Astrocytoma Usually lacks markers like AFP or β-hCG; different cellular origin
Pineal parenchymal tumour Typically arises from pineal gland; different cellular origin