Fiber management structures for fan-out assemblies that are used to furcate a fiber optic cable are disclosed, as are fiber optic assemblies with fiber management structures and related methods. The fiber management structures each include channels extending between opposed first and second ends. A plurality of fan-out tubes are received in the plurality of channels such that the fiber management structure organizes the fan-out tubes, thereby allowing a compact furcation body to be formed even when furcating high fiber count cables.