Definition
High grade carcinomas resembling those of the bronchial tree, including both small cell carcinoma and large cell neuroendocrine carcinoma. The corresponding low grade tumours are carcinoids of the ampulla of Vater.
These are predominantly tumours of the elderly, more common in males.
Small cell carcinomas show cells that grow in sheets, sometimes forming rosettes. Necrosis is extensive. The mitotic rate exceeds 50/10HPF. Small cell carcinoma may occur in combination with adenoma and/or adenocarcinoma.
Large cell carcinoma shows a variable nested, trabecular, rosetting or organoid pattern of growth. There may be a hyalinised or myxoid stroma. The cells have prominent nucleoli. Necrosis is extensive. The mitotic rate is high.
High grade neuroendocrine carcinomas are positive for one or more neuroendocrine marker, usually for two or more. (Poorly differentiated ampullary adenocarcinomas show at most staining of a few scattered cells.)
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|
High-grade neuroendocrine carcinoma |
Poorly differentiated ampullary adenocarcinoma |
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|
0/121 |
||||
|
12/131 |
4/121 |
|||
|
5/81 |
0/111 |
|||
|
6/91 |
12/121 |
|||
|
11/111 |
12/121 |
|||
|
7/81 |
8/111 |
|||
|
3/81 |
6/111 |
|||
|
2/71 |
6/121 |
|||
|
8/91 |
0/111 |
|||
|
4/101 |
12/121 |
|||
|
8/91 |
8/111 |
|||
|
0/91 |
0/111 |
|||
|
MIB1 (mean % of cells) |
63%1 |
50%1 |
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There is a favorable but short-lived responsiveness, particularly of small cell carcinoma, to platinum-based chemotherapy.
These are aggressive tumours, with a high frequency of distant metastases. There may be a propensity for cerebral metastases.
This page last revised 28.6.2005.
©SMUHT/PW Bishop