Jung-Eun Cheon MD, Presenter: Nothing to Disclose

In-One Kim MD, Abstract Co-Author: Nothing to Disclose

Woo Sun Kim MD, Abstract Co-Author: Nothing to Disclose

Su-mi Shin MD, Abstract Co-Author: Nothing to Disclose

Kyung Mo Yeon MD, Abstract Co-Author: Nothing to Disclose

To describe the MR imaging appearance of germ cell tumors (GCT) in the basal ganglia and thalamus and their temporal changes.

Twenty-four patients with pathologically confirmed GCT involving basal ganglia and thalamus (mean age 12.5 years; range 7-18 years, 92% boys) were retrospectively evaluated. All patients were confirmed as GCT by stereotactic biopsy or excision of the tumor [germinoma (n=22), mixed germ cell tumor (n=1) and mature teratoma (n=1)]. MR images prior to diagnosis were available in eight patients. MR imaging analysis was focused on the morphology and signal characteristics of the tumor, atrophy of ipsilateral cerebral peduncle, and temporal changes of the tumors. Germinoma with negative serum tumor markers (HCG/αFP) were compared with germinoma with positive tumor markers.

GCT involving the basal ganglia and thalami were unilateral in 22 patients (92%) and bilateral in two patients (8%). Tumors (n=26) were mostly cystic with solid portion (n=14, 54%), mostly solid with a few tiny cysts (n=7, 27%), or ill-defined, subtle signal changes on T2WI (n=5, 19%) at the time of diagnosis. Solid portion of the tumor was isointense relative to the cerebral cortex for all MR pulse sequences. The cystic portion showed various signal intensity on T1WI. Intratumoral hemorrhage with fluid-fluid level was seen in seven lesions. In 22 patients with unilateral lesions, ipsilateral rainstem atrophy was found in 17 patients (81%). Patients with ill-defined lesions showed ipsilateral atrophy of the basal ganglia in all patients. Enhanced T1WI showed heterogeneous enhancement in the solid portions, peripheral enhancement of the cystic portions, and poor enhancement of the ill-defined lesions. In eight patients with follow-up MR images, ill-defined, subtle signal abnormalities in the basal ganglia and thalamus changed into mostly cystic(n=3) or mostly solid lesions (n=2). Germinoma with positive tumor markers showed a lager mass (p< 0.001) with mostly cystic component (p=0.029).

GCT involving the basal ganglia and thalamus showed a spectrum of MR features from ill-defined subtle signal abnormalities to a mixed solid and cystic tumor.

GCT should be included in the differential diagnosis of the ill-defined basal ganglia and thalamic lesion in teenage boy and may require serum/CSF markers and biopsy for diagnosis.

Cheon, J, Kim, I, Kim, W, Shin, S, Yeon, K, Basal Ganglia and Thalamic Germ Cell Tumors in Children: Spectrum of MR Features.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6020804.html