Clinical features, radiologic findings, and treatment of pediatric germ cell tumors involving the basal ganglia and thalamus: a retrospective series of 15 cases at a single center.

Purpose: Pediatric germ cell tumors (GCTs) involving the basal ganglia and thalamus are relatively rare neoplasms which have not been extensively described. We here summarize the clinical and radiological features of a series of such tumors and discuss optimal treatment strategies based upon our experience.

Methods: A total of 15 pediatric patients with basal ganglionic and thalamic GCTs were treated between 2011 and 2016 at West China Hospital. Epidemiological characteristics, clinical features, imaging findings, and treatment strategies were reviewed retrospectively.

Results: GCTs constituted 28% (15/53) of pediatric basal ganglionic and thalamic tumors in our institution between 2011 and 2016. There were 12 males and 3 females with mean age of 11.7 ± 2.8 years (range, 7-16 years). The most common initial manifestation was hemiparesis (n = 13, 86.7%), followed by headache (n = 5, 33.3%), vomiting (n = 3, 20.0%), cognitive disturbance (n = 2, 13.3%), and seizure (n = 1, 6.7%). No tumors were incidentally detected. The mean duration of the symptoms before diagnosis was 4.4 ± 3.9 months (range from 9 days to 13 months). The maximum diameters of the lesions ranged from 3.2 to 6.5 cm (mean 4.7 ± 1.1 cm). Cysts were seen in tumors in MRIs in 11 patients (73%), intratumoral hemorrhages in 3 (20%), calcification in 2 (13%), and there was obstructive hydrocephalus in 1 (7%). Of note, hemiatrophy was observed in 9 cases (60.0%). The mean follow-up for the 15 patients was 28 months (range, 9-54 months), and no patients were lost. During the follow-up period, all patients (9 cases) with germinomas responded well to radiotherapy, and no recurrence was observed. Among 4 patients with mixed nongerminomatous germ cell tumor, 2 suffered tumor recurrence after treatment. Neurological deficits improved or remained unchanged in 12 patients but 3 developed new dysfunction including significant cognitive disturbance and hemiparesis.

Conclusions: Pediatric GCTs in the basal ganglia and thalamus are not as rare as previously considered. Tumor markers should be tested routinely for tumors in these sites in young patients. Optimal treatment strategy based on accurate diagnosis and comprehensive clinical assessment should be recommended.