Primary suprasellar germinoma: A retrospective study of 15 cases

The aim of the present study was to investigate the clinical characteristics, treatments and outcomes of patients with primary suprasellar germinoma, a rare malignant brain tumor. In the present study, the medical data of 15 cases of primary suprasellar germinoma were retrospectively reviewed. The basic clinical characteristics, primary symptoms, admission period, surgical treatment, radiotherapy and chemotherapy, and follow-up were analyzed. There were 6 female (40%) and 9 male (60%) patients, with a mean age of 19.6 ± 7.4 years (age range, 9–39 years). The mean admission period was 17.0 ± 19.0 months (range, 0.5–260 months), and the mean follow-up period was 28.8 ± 21.5 months (range, 4–70 months). The primary complaints were polydipsia and polyuria (66.7%) and visual impairment (53.3%); 2 cases (13.3%) were affected in both the suprasellar and the pineal regions. In all 15 cases, a diagnosis of germinoma was histopathologically confirmed by craniotomy or biopsy, though gross total resection was only achieved in 1 patient. No instances of surgical mortality were observed. After surgery, all patients underwent radiotherapy and chemotherapy, and all recovered well following discharge. During follow-up, symptoms were markedly relieved and a reduction in tumor size was observed in all cases. However, 1 patient died 4 months post-surgery due to progressive disturbance of consciousness and severe pulmonary infection. In conclusion, primary suprasellar germinoma is a rare malignant brain tumor, of which progressive polydipsia and polyuria, and visual impairment are the primary symptoms. Thickening of the pituitary stalk may be the only initial imaging manifestation. Craniotomy for partial resection or endoscopic biopsy is strongly recommended to confirm histological diagnosis. Whole ventricular radiotherapy plus local enhanced radiotherapy, or combined radiotherapy and chemotherapy, are effective at reducing tumor size and relieving symptoms. Prognosis is favorable for most patients with primary suprasellar germinoma, though endocrine deficiencies should be managed appropriately.

RARE-28. HYPOTHALAMIC GERMINOMA AND NEUROSARCOIDOSIS: A TALE OF TWO PATHOLOGIES

CASE 1: 30-year-old Caucasian male with a history of hereditary cavernomas, testicular germ cell tumor s/p orchiectomy 2017 presented next year with a chief complain of increasing lethargy. MRI Brain showed a new expansile, homogenously enhancing hypothalamic lesion causing obstructive dilatation of the lateral ventricles. MRI of neuraxis was not concerning for leptomeningeal spread. Initial differentials included suprasellar germinoma vs chiasmatic hypothalamic glioma vs metastatic lesion. Biopsies X2 showed gliosis and granulomatous inflammation. Despite radiation treatment for the hypothalamic mass clinical course continued to deteriorate. CSF results showed RBC - 1,200; WBC - 51 with 77% lymphocytes, 3% neutrophils, 20% monocytes. FDG-PET did not reveal evidence of metastatic disease. He was treated presumptively for neurosarcoidosis with high-dose corticosteroids and azathioprine and later transitioned to methotrexate and infliximab. Follow up MRI scans showed a reduction in the hypothalamic mass. CASE 2: A 23-year-old African American male treated for ADEM in 2010 presented to clinic with behavioral problems in 2017. Initial presentation included lethargy with imaging showing an incidental hypothalamic mass. Initial differentials included germinoma vs infundibular hypophysitis vs granulomatous process. He was treated with immunotherapy (corticosteroids and IVIG) with partial resolution of the growth. He was later diagnosed with suprasellar germinoma on biopsy subsequently treated with 2 cycles chemotherapy and proton beam radiotherapy in 2012. In 2017. to exclude tumor recurrence an LP showed elevated ACE however remainder of the clinical picture was not suggestive of neurosarcoidosis. DISCUSSION: Multiple case series have been described wherein hypothalamic germinoma mimics isolated neurosarcoidosis and vice-versa. Because of similar clinical picture and radiographic findings, the diagnosis is challenging. ACE is a nonspecific test for neurosarcoidosis, and it can be positive in the setting of germinoma as well. Hence specific molecular markers may be helpful in the diagnosis.

Is there variable neuronal susceptibility to compression?

A 12-year-old boy with suprasellar germinoma complicated by hydrocephalus was found to have dorsal midbrain syndrome and bilateral compressive optic neuropathy. Following a third ventricular neuroendoscopic biopsy and the initiation of chemotherapy, a follow-up magnetic resonance imaging scan of the brain showed significant regression of the tumor with resolution of hydrocephalus. On smooth pursuit, there was significant improvement in upgaze. However, light-near dissociation of his pupillary defect was persistent. Fundal examination showed persistent temporal pallor of the optic discs bilaterally, associated with a suboptimal best-corrected visual acuity of 20/40 and bilateral centrocecal scotoma.The differential recovery of neuronal function following relief of compression is poorly understood. In this case, both the optic nerve and pretectal axonal fibers responsible for pupillary reflex, with their neuronal cell bodies residing outside the direct compressive site at the midbrain, showed poor functional recovery. However, relief of pressure at the rostral interstitial medial longitudinal fasciculus and posterior commissure nuclear complexes resulted in significant clinical improvement in upgaze. This case suggests that, for neurons, axons are apparently more susceptible to pressure than cell bodies. The predominant transmission of nerve impulses takes place through the length of axons, and thus is more sensitive to pressure changes, with the associated microvascular compromise and demyelination.