A 32 yr old male patient, in whom a left temporo-parietal craniectomy had been carried out to gain access to, and treat an astrocytoma. A The excised bone flap was preserved in his abdominal wall. B 7 months later, the autologous bone flap was retrieved and re-implanted. C, D Palpable collection of fluid which developed beneath the scalp flap, 14 days following the autologous bone cranioplasty