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13 August 2014 - Case of the Week #322

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Case of the Week #322

Clinical History:
A 50 year old man with obstructive jaundice had an ampullary mass. A biopsy was followed by the Whipple procedure (pancreaticoduodenectomy).

Micro images:

What is your diagnosis?

Collision tumor-mixed adenoneuroendocrine carcinoma of the duodenum (> 30% each component)


Immunostains were obtained:




Figure 1: shows invasive poorly differentiated adenocarcinoma of the duodenum
Figure 2: epithelioid cells with irregular, hyperchromatic and pleomorphic nuclei, and small amount of cytoplasm
Figure 3: shows poorly differentiated adenocarcinoma
Figure 4: lymph node metastasis of neuroendocrine carcinoma
Figure 5: IHC shows weak but diffuse positivity for CDX2
Figure 6: lymph node is diffusely positive for synaptophysin (and patchy for chromogranin); negative for CK7 and CK20
Figure 7: ampullary adenocarcinoma is negative for synaptophysin

In addition, many cells are positive for CK20, occasional cells are positive for CK7.

Collision tumor is a well documented but uncommon phenomenon characterized by (a) two distinctive and spatially independent tumor components in the same location and (b) distinct and well demarcated morphology and immunoexpression patterns between the two tumors microscopically, with no intervening intermediate cell populations. This entity is distinct from neoplasms demonstrating heterologous or mixed elements. Collision tumors in general, and those involving adenocarcinoma and neuroendocrine carcinomas in particular, are extremely rare in the duodenum (Rare Tumors 2012;4:e20, Gut 2001;48:853), ampulla (Rev Esp Enferm Dig 2007;99:235, HPB Surg 1997;10:241) and stomach (Case Rep Gastroenterol 2014;8:89).

The differential diagnosis includes adenocarcinoma with neuroendocrine features.

Nat Pernick, M.D., President
and Shivani Thakore, Associate Medical Editor
PathologyOutlines.com, Inc.
30100 Telegraph Road, Suite 408
Bingham Farms, Michigan (USA) 48025
Telephone: 248/646-0325
Email: NatPernick@Hotmail.com
Alternate email: NatPernick@gmail.com