Loco-regional extensions of central nervous system germ cell tumors: a retrospective radiological analysis of 100 patients.

PURPOSE

The current staging system of central nervous system (CNS) germ cell tumors (GCT) includes a binary classification in "localized" or "metastatic" disease based on the absence or presence of leptomeningeal dissemination. Loco-regional tumor dissemination has been barely described whereas its accurate definition might be useful in terms of prognosis and treatment, especially for radiation therapy planning. Our purpose was therefore to describe MR patterns and prevalence of loco-regional extensions of these tumors.

METHODS

One hundred consecutive patients (median age 16.3 years, range 7-41 years, sex ratio 7:1) with a histologically or biologically proven CNS GCT were retrospectively included. Brain and spinal MRI at diagnosis were reviewed by two neuroradiologists focusing on MR patterns of primaries and loco-regional extensions. When available, follow-up MR exams were analyzed.

RESULTS

Pure germinoma represented 84/100 cases. Primaries were unifocal pineal (n = 49/100), bifocal pineal and supra-sellar (n = 27/100), isolated supra-sellar (n = 21/100), isolated basal ganglia (n = 2/100) or trifocal pineal, supra-sellar, and basal ganglia (n = 1/100). Metastatic disease occurred in 6/100 patients (depicted by MRI in two and CSF cytology in four). Loco-regional extensions were observed in all patients and classified as follows: third ventricle (n = 88/100), thalamus (n = 47/100), midbrain (n = 42/100), distant sub-ependymal areas (n = 19/100), optic pathways (n = 19/100), lateral ventricles (n = 7/100), cavernous sinus (n = 6/100), corpus callosum (n = 4/100), and fourth ventricle (n = 3/100).

CONCLUSION

CNS GCT present with specific loco-regional extensions at diagnosis. Improving their recognition will be helpful to further understand their prognostic value and potentially to optimize the treatment.