In conventional Raman spectroscopic measurements of liquids or surfaces the preferred geometry for detection of the Raman signal is the backscattering (or reflection) mode. For non‐transparent layered materials, sub‐surface Raman signals have been retrieved using spatially offset Raman spectroscopy (SORS), usually with light collection in the same plane as the point of excitation. However, as a result of multiple scattering in a turbid medium, Raman photons will be emitted in all directions. In this study, Monte Carlo simulations for a three‐dimensional layered sample with finite geometry have been performed to confirm the detectability of Raman signals at all angles and at all sides of the object. We considered a non‐transparent cuboid container (high density polyethylene) with explosive material (ammonium nitrate) inside. The simulation results were validated with experimental Raman intensities. Monte Carlo simulation results reveal that the ratio of sub‐surface to surface signals improves at geometries other than backscattering. In addition, we demonstrate through simulations the effects of the absorption and scattering coefficients of the layers, and that of the diameter of the excitation beam. The advantage of collecting light from all possible 4π angles, over other collection modes, is that this technique is not geometry specific and molecular identification of layers underneath non‐transparent surfaces can be obtained with minimal interference from the surface layer. To what extent all sides of the object will contribute to the total signal will depend on the absorption and scattering coefficients and the physical dimensions. Copyright © 2015 John Wiley & Sons, Ltd.

Dermoid cysts are rare congenital lesions of the brain. They are commonly located in the supratentorial region. Infratentorial dermoid cysts are uncommon. They can occupy cerebellopontine angle, midline posterior fossa, or brain stem. Midline post fossa dermoid cysts can be confused with another common lesion in this location. We describe a case of midline posterior fossa dermoid cyst in a 6-year-female child who presented with signs and symptoms of raised intracranial pressure. Magnetic resonance imaging showed posterior fossa lesion which was hypointense on T1-weighted images, hyperintense on T2-weighted images, and not enhancing on intravenous contrast administration. The lesion showed restricted diffusion on diffusion-weighted images. Radiological diagnosis was an epidermoid cyst. However, during surgery, we found hair follicles. Histopathological examination revealed dermoid cyst. The child recovered completely following cyst excision. We present a case of a posterior fossa dermoid cyst mimicking epidermoid cyst.

Vestibular schwannomas (VSs) are tumors that commonly occur in the eighth cranial nerve. They are usually associated with type 2 neurofibromatosis. They are uncommon in children, and sporadic cases of pediatric VS are even rarer. In general, VSs are benign lesions with less than 1% chance of intratumoral hemorrhage. Adult cases of hemorrhage in VS are well documented. We present the first pediatric case of intratumoral hemorrhage in VS in the absence of any features of NF in an 11-year-old child who complained of holocranial headache and sensorineural hearing loss in the left ear. We further discuss the pathogenesis and clinical features, and review the literature of intratumoral hemorrhage in patients of VS.

Intraparenchymal meningiomas, meningiomas without dural attachment, and cystic meningioma are atypical and extremely rare, especially in adults. Only four cases of intraparenchymal cystic meningioma without dural attachment have been reported. A 47-year-old female presented with an altered sensorium. She had a progressive bifrontal headache for 2 months. Computed tomography scan of the brain showed an 8 cm × 6 cm cystic lesion with a solid component in the left frontoparietal region with a midline shift. The solid part of the lesion was enhancing on contrast but the cyst rim was not. Intraoperatively, the cyst was filled with amber-colored fluid, which was drained, and the solid component was completely excised. Histopathological examination of the solid tumor component confirmed cystic meningioma. At 2 years of follow-up, she has no evidence of recurrence. We report the fifth case of this very rare entity and review the literature.