However, in Japan they represent a much higher percentage of malignancies in the ovary (almost 20%) due to the increased prevalence of gastric cancer.Krukenberg tumors account for about 15% of metastatic cancers that initially appear to have arisen in the ovary, and as such is less common than metastasis arising from ovarian epithelial and germ-cell tumors.In people who have had nongynecologic malignancy, approximately 20% of adnexal masses are malignant, and 60% of these are Krukenberg tumors. Pathogenesis
There has been debate over the exact mechanism of metastasis of the tumor cells from the stomach, appendix or colon to the ovaries. Classically it was thought that direct seeding across the abdominal cavity accounted for the spread of this tumor, but spread by way of the lymphatic is considered more likely. Retrograde lymphatics are thought to be more important in the pathogenesis of Krukenberg tumour, since the ovaries in Krukenberg tumour do not show capsular invasion or a breech of the epithelium lining the surface. The average age of diagnosis of Krukenberg tumors may partly relate to the relatively increased vascularity of the ovaries.Microscopically, Krukenberg tumors are often characterized by mucin-secreting signet-ring cells in the tissue of the ovary; when the primary tumor is discovered, the same signet-ring cells are typically found. However, other microscopic features can predominate.
Focal seizures (also called partial seizures and localized seizures) are seizures which affect initially only one hemisphere of the brain. The brain is divided into two hemispheres, each consisting of four lobes – the frontal, temporal, parietal and occipital lobes. A focal seizure is generated in and affects just one part of the brain – a whole hemisphere or part of a lobe. Symptoms will vary according to where the seizure occurs. When seizures occur in the frontal lobe the patient may experience a wave-like sensation in the head. When seizures occur in the temporal lobe, a feeling of déjà vu may be experienced. When seizures are localized to the parietal lobe, a numbness or tingling may occur. With seizures occurring in the occipital lobe, visual disturbances or hallucinations have been reported. Types
As of 2017, focal seizures are split into two main categories, focal onset aware, and focal onset impaired awareness. What was previously termed a secondary generalised seizure is now termed a focal to bilateral seizure.In focal onset aware seizures, a small part of one of the lobes may be affected and the person remains conscious. This can often be a precursor to a larger focal onset impaired awareness seizure. When this is the case, the focal aware seizure is usually called an aura. A focal impaired awareness seizure affects a larger part of the hemisphere and the person may lose consciousness.