Germinoma
BASIC DESCRIPTION
- Intracranial germ cell tumor, often occurring in the pineal region (extragonadal seminoma/dysgerminoma)
PATHOLOGY
- WHO grade II (pure germinoma) or grade III (syncytiotrophoblastic giant cells)
- Associated with Down and Klinefelter syndromes and neurofibromatosis type 1 (NF-1)
- Polygonal primitive germ cells and lymphocytic infiltrates are common microscopic features
- Single or multiple tumors can occur
- Multiple tumors are considered metastatic rather than synchronous in the United States
CLINICAL FEATURES
- Children and young adults usually afflicted (90% are <20 years old)
- Marked male gender predilection (10–33:1) in pineal-region germinomas
- Females afflicted more commonly with suprasellar germinomas
- Common presenting signs/symptoms
- Pineal region: headache due to mass effect on tectum and ventricular obstruction at the cerebral aqueduct, Parinaud syndrome (upgaze palsy)
- Suprasellar: endocrine dysfunction (diabetes insipidus, precocious puberty), visual field defects
- Laboratory findings: increased serum/cerebrospinal fluid (CSF) beta-human chorionic gonadotropin (β-hCG) level
- Treatment: biopsy, low-dose radiation ± chemotherapy
- Positive prognosticators include mild elevation of β-hCG level and pure (WHO grade II) germinoma histology
- Invasion and CSF dissemination commonly occur
IMAGING FEATURES
- General
- Mass within pineal or suprasellar region at or near midline
- Engulfs pineal gland, can accelerate pineal calcification
- Basal ganglia uncommonly involved
- Single or multiple locations (metastatic)
- Often infiltrates into ventricles, midbrain, thalamus; ±CSF dissemination
- CT
- Lobulated, hyperdense mass
- ±Cysts, hemorrhage
- Avid, homogeneous enhancement on contrast-enhanced CT ± CSF dissemination
- MRI
- T1WI: isointense to hyperintense; normal posterior pituitary “bright spot” may be absent in suprasellar germinoma
- T2WI: isointense to hyperintense; foci of hemorrhage appear hypointense; hyperintense areas of cysts or necrosis
- FLAIR: mildly hyperintense
- DWI: diffusion restriction due to hypercellularity
- T1WI+C: avid, homogeneous enhancement including areas of CSF dissemination and parenchymal invasion
- MRS: elevated Cho, decreased NAA
IMAGING RECOMMENDATIONS
- MRI without and with intravenous contrast including brain and spine to detect metastases
For more information, please see the corresponding chapter in Radiopaedia.
Contributor: Rachel Seltman, MD
References
Jinguji S, Yoshimura J, Nishiyama K, et al. Factors affecting functional outcomes in long-term survivors of intracranial germinomas: a 20-year experience in a single institution. J Neurosurg Pediatr 2013;11:454–463. doi.org/10.3171/2012.12.PEDS12336.
Liang L, Korogi Y, Sugahara T, et al. MRI of intracranial germ-cell tumours. Neuroradiology 2002;44:382–388. doi.org/10.1007/s00234-001-0752-0.
Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Elsevier, Philadelphia, PA; 2016.
Sawamura Y. WHO histological classification of tumors of the central nervous system: germ cell tumors (WHO, 1993). In Sawamura Y, Shirato H, de Tribolet N (eds). Intracranial Germ Cell Tumors. Springer, Vienna, Austria; 1998:3–4. doi.org/10.1007/978-3-7091-6821-9_2.
Ueno T, Tanaka YO, Nagata M, et al. Spectrum of germ cell tumors: from head to toe. Radiographics 2004;24:387–404. doi.org/10.1148/rg.242035082.
Vasiljevic A, Szathmari A, Champier J, et al. Histopathology of pineal germ cell tumors. Neurochirurgie 2015;61:130–137. doi.org/10.1016/j.neuchi.2013.06.006.
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