Device and method for rapid extraction of body tissue from an enclosed body cavity. Hollow entry cannula with optional core element provides entry into body tissue space such as bone marrow. Aspiration cannula is inserted through cannula into body tissue and is manipulated to advance directionally through body cavity. Optional stylet within aspiration cannula aids in advancing aspiration cannula through body tissue and is removed to facilitate extraction of body tissue through the aspiration cannula. Inlet openings near distal tip of aspiration cannula allow tissue aspiration, with negative pressure source at proximal end of aspiration cannula providing controlled negative pressure. Aspiration cannula may be withdrawn and its path adjusted for multiple entries through the same entry point, following different paths through tissue space for subsequent aspiration of more tissue.