The other option is that it was a meat spot. This is where a piece of tissue breaks away in the oviduct. It usually travels through the system with a yolk but the hen's body can treat the tissue like an egg and encapsulate it in egg white and a shell. I'm not good at doing links but if you search the term meat spot in eggs, you should get something. Most are very small blood spots with yolks but it is possible for larger pieces of tissue with no yolk. Did your egg have normal-ish translucent white. A lash egg is usually rubbery and solid and doesn't have a white and shell, although many variations are possible. A lash egg is concerning because it usually denotes salpingitis, which is an infection of the oviduct, whereas a meat spot may just be a one off minor abnormality of the system.