Retrieval devices and methods for retrieving tissue

According to the invention, in order to remove tissue, in particular pathogen tissue, from a body cavity of a patient, a removal device is provided having a removal bag (12) which is completely or partially formed from a hydrophilic, water-permeable filter membrane (26). The filter membrane (26) comprises a pore width preferably less than 12 [mu] m, further preferably less than 8 [mu] m, and preferably less than 5 [mu] m in order to reliably avoid passage of pathogen cells or other pathogen materials. However, the aperture is at least large such that water can be easily removed from the extraction bag (12). In this manner, the removal bag (12), when filled, only requires the volume occupied by the contained tissue to be removed. The liquid provided within the extraction bag (12) can be discharged from the extraction bag through the filter membrane (26) and thus does not increase its volume. This allows for the accommodation of relatively large tissue blocks during tumor removal. Thus, tumors can be removed as