46-year-old female with melaena. The CT scan reveals small tumour
in the middle part of the ileum. Partial resection of the ileus.
- The specimen originates from the small bowel wall with parts of
a Peyer`s patch.
- At one point a tumour is expanding within the submucosa, which
consists of irregularly shaped cell groups. The tumour is well demarcated
but infiltrates the innermost layers of the muscularis propria as
well as the mucosa, which is ulcerated at the centre of the tumour.
-The individual tumour groups are made up by notably regular population
of cells of moderate size and low mitotic activity. Often the cells
align at the periphery into palisades.
-Immunohistochemistry stains show the presence of substance P (in
a brown reaction product) in many tumour cells and also some disseminated
cells of the endocrine system in the normal small bowel mucosa.