1. Departments of Surgery, Histopathology, and Oncology, Imperial College School of Medicine, Hammersmith Hospital, London, W12 0NN, UK.
2. Division of Surgery, El Hyatt Hospital, Heliopolis, Cairo, Egypt.
3. Division of Medicine, Cairo University Medical School, Cairo, Egypt.
4. Department of Surgery, Theodor Bilharz Institute, Imbaba, Cairo, Egypt.