Spontaneous complete regression of a brain stem glioma pathologically diagnosed as a high-grade glioma.

BACKGROUND: Spontaneous regressions of brain stem gliomas are extremely rare. Only six cases have been reported in the literature. CASE PRESENTATION: We describe the case of a patient who was diagnosed with a pontomedullary dorsal brain stem glioma at the age of 15 years. An open biopsy showed the presence of an anaplastic glioma. Because the patient and her parents refused conventional therapies, including radiation and chemotherapy, we followed up the patient by performing magnetic resonance imaging scans on her every 3 months. At 3 months after biopsy, we observed the radiological disappearance of her tumor. One year after biopsy, the tumor retained the spontaneous complete regression observed earlier. CONCLUSION: In this case report, we present the first report of the spontaneous complete regression of a brain stem glioma that was histologically proven to be a high-grade glioma and we believe that this regression was the natural progression of this case, as may be the scenario in a few other cases of brain stem gliomas.

Form birefringence in intrinsic birefringent media possessing a subwavelength structure.

We theoretically investigate optical birefringence originating from subwavelength structures in intrinsic birefringent media. Assuming alternating layers of isotropic and anisotropic materials, the propagation of optical waves is simulated on the basis of the finite difference time domain method. Optical polarization changes throughout the structure reveal the birefringence of the layered structure as a whole. In addition, the birefringence is also analyzed on the basis of effective medium theory. The results indicate that the optical birefringence of the structure as a whole can be modified by the magnitude and direction of the intrinsic birefringence of the anisotropic layers. This theoretical prediction will be useful for micro- and nanofabrication in optical devices.