General
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• Rare variant of adenocarcinoma, with fewer than 20 cases reported (Oncol Lett 2014;8:1873)
• Demonstrates clear cell features due to intracytoplasmic glycogen

Epidemiology
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• Usually arises in men, in the descending colon (J La State Med Soc 2014;166:143)

Pathophysiology
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• Can arise from a tubular adenoma also showing clear cell morphology (Am J Surg Pathol 2010;34:1344)

Case reports
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• 41 year old woman with clear cell adenocarcinoma of the colon (Case Rep Oncol Med 2014 Mar 4:905478)
• 65 year old woman with clear cell adenocarcinoma of the colon arising in endometriosis (J Clin Pathol 2001;54:76)
• 68 year old man with clear cell adenocarcinoma of the colon (J Clin Pathol 1995;48:1142)
• 81 year old man with clear cell adenocarcinoma with enteroblastic differentiation (J Clin Oncol 2011;29:e647)
• 89 year old woman with clear cell adenocarcinoma of the colon (Int J Colorectal Dis 2004;19:264)

Clinical images
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Stenotic tumor on colonoscopy

Micro description
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• Resembles normal colorectal adenocarcinoma, except cells show prominent cytoplasmic clearing

Micro images
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Glandular arrangement of clear cells

Vesicular nuclei and prominent nucleoli

 

Prominent vesicular and pleomorphic nucleoli

H&E, CDX2+

AFP+

Positive stains
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• CK20, CDX2, weak MUC2 (Am J Surg Pathol 2010;34:1344)

Negative stains
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• CK7 (Am J Surg Pathol 2010;34:1344)

Differential diagnosis
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• Metastatic clear cell renal cell carcinoma: PAX8+

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