An apparatus includes a flexible container and a port. The container includes a first layer coupled to a second layer to define a storage volume within which a tissue specimen can be contained. The first layer has a first stiffness and the second layer has a second stiffness. An edge of the first layer is spaced apart from an edge of the second layer to define an opening into the storage volume. The edges of the first and second layer form a peelable seal that hermetically seals the storage volume such that the first layer can be peeled away from the second layer to expose the storage volume. The port is coupled to the flexible container and allows fluid communication between the storage volume and an external volume.