This is the distal half of an appendix. The tip is occupied by a discrete yellow-coloured tumour
which does not extend through to serosa.
This patient presented with acute abdominal pain at the age of 18. An appendectomy
was performed and the appendix showed evidence of inflammation (not shown in the specimen) as
well as tumour. A carcinoid tumour in the appendix is nearly always benign. It is formed from the
neuroendocrine (or argentaffin) cells in the mucosa. The term argentaffin refers to the ability of
the cells to reduce silver salts when appropriately stained. The yellow colour in the lesion is due