Since severe acute respiratory syndrome-coronavirus-2 variant B.1.1.529 (omicron) was first reported to the World Health Organization on November 24, 2021, the cases of the omicron variant have been detected in more than 90 countries over the last month. We investigated the clinical and epidemiological characteristics of the first 40 patients with the omicron variant who had been isolated at the National Medical Center in South Korea during December 4–17, 2021. The median age of the patients was 39.5 years. Twenty-two patients (55%) were women. Seventeen patients (42.5%) were fully vaccinated, and none were reinfected with the omicron. Eighteen (45%) had recent international travel history. Half of the patients (19, 47.5%) were asymptomatic, while the others had mild symptoms. Six patients (15%) showed lung infiltrations on chest image; however, none required supplemental oxygen. These mild clinical features are consistent with recent case reports on the omicron variant from other countries.

The antibody responses to influenza vaccination on days 1 and 11 during a 3-week cytotoxic chemotherapy cycle were comparable. Influenza vaccination can be performed concurrently with cytotoxic chemotherapy or during the cytopenic period. Cancer 2017;123:841-48. © 2016 American Cancer Society.

Sclerosing meningioma is a distinct histologic subtype of meningioma, however, it is often confused with other tumors, especially malignant tumors. To widen our knowledge of sclerosing meningioma and to help neurosurgeons and neuropathologists diagnose this clinically and pathologically unfamiliar disease entity, we reviewed four such cases, which were originally misdiagnosed. Sclerosing meningiomas were assessed for cellularity, cellular pleomorphism, mitotic activity, brain invasion, and necrosis. Immunohistochemical staining was performed on paraffin-embedded sections using the avidin-biotin-peroxidase complex method. The histologic appearance of the underlying cerebral parenchyma invasion by tumor cells led to a diagnosis of malignant meningioma or to the completely erroneous diagnosis of ganglioglioma. The most conspicuous histologic finding of these four sclerosing meningiomas was extensive collagen deposition, so called 'sclerosis' and an intermingled small population of spindle or round cells with clear cytoplasmic halos, giving a 'fried egg' appearance. However, a typical meningothelial whorl pattern was identified in all cases. Tumor cells exhibited positive immunoreactivity for epithelial membrane antigen and vimentin, but were negative for glial fibrillary acidic protein, p53, S-100, and neuronal markers. Proliferative indices, using Ki-67, ranged from 0% to 4%, and brain invasion was present in three of four tumors. All four patients are doing well with no evidence of tumor recurrence (follow-up duration of 25 months to 12 years). Brain invasion needs to be re-evaluated as a criterion of malignancy in meningioma. Special attention should be paid to the diagnosis of this subtype of meningioma to prevent unnecessary postoperative radiotherapy and to ensure correct therapeutic decision.

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