Fig. 4.

The magnetic resonance image and endoscopy at presentation demonstrated a polypoid tumor within the low rectum. This infiltrated the muscularis propria, but there was no mesorectal breach. It was staged T2 N0 (arrows, A-C). Following local resection, chemoradiotherapy and a Papillon boost, a “black spider” appearance is seen with fibrosis at the treated tumor site (arrow, D). The coronal image shows some residual intermediate signal at this time (arrow, E). Endoscopy revealed no evidence of recurrence (F). At 1-year follow-up, on magnetic resonance imaging, the fibrosis continued to mature, with no residual intermediate signal tumor remaining (arrows, G, H). On endoscopy, stenosis and ulceration was seen, but no recurrence (I). However, 1.5 years post-treatment, intermediate signal tumor recurrence is seen at the periphery of the fibrotic crater with loss of black fibrosis seen at the anterior margin extending beyond the scar (arrows, J, K). On endoscopy, a recurrent malignant mass was apparent (L)