Embodiments relate to expandable tissue cavity markers and corresponding systems and deployment methods. In one embodiment, an expandable tissue cavity marker comprises a pouch and at least one radiopaque marker element. The pouch can transition between a compressed state, in which a profile or dimension of the tissue cavity marker is reduced such that the tissue cavity marker can be deployed through a minimally invasive surgical procedure incision, and an expanded state, in which a profile or dimension of the tissue cavity marker is increased such that the tissue cavity marker fills or defines a volume of a tissue cavity. In one embodiment, the pouch can be transformed between the compressed state and the expanded state by delivery of a fill material into the pouch. The pouch can comprise one or more functional materials in embodiments, including materials that provide an anti-infection, hemostasis, anti-migration, medicinal, or other function to the tissue cavity marker.
