CASE 2 CLOUSTON Anal adenocarcinoma final.pages

Pathology The mass was localised to one quadrant of the anal canal and radical local excision was attempted to preserve continence. There was an ellipse of mucosa and anal skin with deep tissues. The mucosal surface was scarred from the chronic fistula, but had no mass lesion evident. Sectioning showed a loculated mucinous lesion. Histologically, the tumour was a very well differentiated mucinous adenocarcinoma. In many areas acellular mucin dissected through the tissues. When present, the epithelium lining the mucin-filled spaces was atypical, ranging from only subtle nuclear crowding and mild loss of polarity to more obvious but still relatively mild pleomorphism. The epithelium was predominantly flat or was thrown into low amplitude papillary folds. The stroma was bland collagenous tissue. The tumour cystic spaces extended into the muscularis propria, and focally reached the peripheral resection margin.