Calvarial hemangiomas: report of two cases and review of the literature.

BACKGROUND: Primary hemangiomas of the bone are uncommon tumors, accounting for less than 1.0% of all bone neoplasms. These tumors are mostly found in vertebral bodies. Hemangiomas are rarely seen in the calvarium, where their frequency is 0.2% of all bone neoplasms. Because of their infrequent appearance in the skull, vague symptoms, and absence of prototypical radiological findings, these tumors can be missed in many cases or may be misinterpreted as more ominous lesions like multiple myeloma or osteosarcoma. CASE DESCRIPTION: We report two cases of calvarial hemangiomas: one with a single mass on the right sphenoid wing, and another with two similar lesions on the right occipital and left parietal bones. The diagnoses could be established only by histopathologic analysis. CONCLUSION: Histopathologic confirmation of the tumor is the definitive method for diagnosis of intraosseous hemangiomas. Radiological findings are not always characteristic for calvarial hemangiomas. Due to possible complications and the possibility of effective treatment, this lesion should always be considered in the differential diagnosis of skull lesions.

Solar Irradiance Change and Special Longitudes Due to r-Modes.

Sluggish global oscillations, having a periodicity of months and trapped in the sun's convection zone, modulate the amount of energy reaching Earth and seem to impose some large-scale order on the distribution of solar surface features. These recently recognized oscillations (r-modes) increase the predictability of solar changes and may improve understanding of rotation and variability in other stars. Most of the 13 periodicities ranging from 13 to 85 days that are caused by r-modes can be detected in Nimbus 7 observations of solar irradiance during 3 years at solar maximum. These modes may also bear on the classical question of persistent longitudes of high solar activity.