Facial Nerve Schwannoma Complicated by Acute Hemorrhage After Treatment with Stereotactic Radiosurgery.

BACKGROUND: Facial nerve schwannomas (FNSs) are rare benign tumors that arise from Schwann cells of the facial nerve. FNSs are similar to vestibular schwannomas in many aspects, yet their infiltrative nature into the facial nerve fascicles warrants a more conservative management approach. In the last decade, stereotactic radiosurgery (SRS) has shown promise in stabilizing or shrinking FNSs. CASE DESCRIPTION: A 71-year-old woman presented with mild facial paresis. Tumor growth after a period of watchful waiting warranted treatment with SRS, which was complicated by an acute posterior fossa hemorrhage and brainstem compression, necessitating microsurgical hematoma evacuation, tumor resection, and facial nerve substitution. CONCLUSIONS: SRS has led to better facial nerve function and outcomes and is currently considered a reasonable alternative to microsurgical resection in patients with FNSs. This is the first report to our knowledge of an acute, life-threatening hemorrhage after SRS in a patient with FNS.

Small lymphaticovenous malformation of the orbital apex clinicopathologic correlation.

PURPOSE: To familiarize clinicians with the clinical and magnetic resonance imaging (MRI) features of a small orbital apex lymphaticovenous malformation that resulted in blindness and evaded timely clinical diagnosis. OBSERVATIONS: A 68-year-old man presented with severe vision loss due to a 9 mm mass at the apex of the orbit above the optic nerve. When surgically removed 4 years later, the lesion was characterized by vascular spaces of varying size. Larger ones were filled with fibrin and organized thrombi. Stromal septa of endothelial-lined cavernous spaces were partially necrotic and there was evidence of remote hemorrhage. Some endothelial cells expressed D2-40, a marker of lymphatic channels. CONCLUSIONS AND IMPORTANCE: Unless a high index of suspicion is maintained for a lymphaticovenous malformation the clinical diagnosis of a small but vision-threatening lesion can be overlooked.

PIK3CA mutation in a mixed dysembryoplastic neuroepithelial tumor and rosette forming glioneuronal tumor, a case report and literature review.

BACKGROUND: Rosette forming glioneuronal tumors are rare, World Health Organization (WHO) grade I novel tumors frequently affecting the fourth ventricle or posterior fossa with typical neuronal pseudorosettes. RGNTs have been described as possessing additional histologic features of DNETs or pilocytic astrocytomas. Activating PIK3CA mutations have been identified as recurring genetic event in RGNTs. METHODS: We report a 35year old man who presented with binocular diplopia, headache, and was found to have a third ventricle tumor. Tumor pathology and oncogene evaluation were conducted. RESULTS: The tumor demonstrated histologic features consistent with mixed RGNT/DNET. Genetic studies revealed a PIK3CA mutation in exon 9 (E545K, C. 1633G>A) without IDH1, p53, 1p19q chromosomal co-deletion, or BRAF mutations. A literature search revealed six cases of PIK3CA mutations in RGNTs and seven cases of mixed RGNT/DNET. No cases of mixed RGNT/DNET with a PIK3CA mutation have been described. CONCLUSION: This is the first documented case of an RGNT/DNET with an activating PIK3CA mutation. The presence of a PIK3CA mutation aids histologic classification in the setting of mixed histology, and may have implications for targeting the PI3K/AKT/mTOR pathway in this tumor type.