Biology of metastasizing XXXX .

@entity1 @entity1567 @entity5 @entity3 @entity204
The present report of a malignant metastasizing @entity1567 and a critical review of literature was undertaken in an attempt to better understand the biological potential and behavior of this rare @entity5 and thus to facilitate its clinical management. Most of the 26 @entity1 with a proven malignant @entity1567 including the present case had developed multiple recurrences. The lung was the most frequent metastatic site (88%) followed by regional lymph nodes (27%). Furthermore @entity3 were observed in some cases in the bone, brain, kidney, small intestine and liver. The interval between diagnosis of @entity5 and manifestation of @entity3 was long with a median of 11.1 years. The average survival time was 13.1 years. By contrast, the interval between diagnosis of @entity3 and @entity204 was relatively short (median: 2.6 years). The histologic and cytologic pattern of malignant @entity1567 and of its @entity3 was not significantly different from that of non-metastatic @entity1567 . Because of the lack of morphological criteria of @entity5 the biological behavior of @entity1567 cannot be predicted. It is difficult to be certain which factors are important in the delayed induction of @entity3 . It is suspected that @entity1567 possess an inherent low grade @entity5 which is stimulated by multiple recurrences. It is further assumed that the @entity3 cells have a slow growth rate resulting in late clinical manifestation of @entity3 . When lung @entity3 occur we recommend their surgical removal in order to prolong live expectancy or even to obtain a curative effect.
