Colorectal clear cell carcinoma: a literature review

Clear cell carcinoma of the colon is a rare entity in colon malignancy. All of the cases involving primary colon clear cell carcinoma are case studies. Since clear cell component can be seen in colon metastasis, adenocarcinoma, and tubular adenoma, precise diagnosis of primary colon clear cell carcinoma is crucial by pathological means. In this study, the main purpose was to focus on the clinical and pathological features of primary colon clear cell carcinoma.

In this review article, we used PubMed, Google Scholar, and ScienceDirect to extract article including data of primary colon clear cell carcinoma. Preferred Reporting Items for Systematic Reviews standards were followed to include and exclude articles.

Out of 340 articles, 18 were eligible for our study based on our inclusion and exclusion criteria. Of the 34 patients diagnosed with colon clear cell carcinoma, 18 were male (53%) and 16 were female (47%) as per gender distribution. The mean age of the patients was 57.6 years old. Abdominal pain/discomfort and gastrointestinal bleeding were the most common symptoms. Tumors were mostly located in descending colon. Cytokeratin had a positive predictive value of (84.6%) and vimentin resembled a negative predictive value of 100%. Caudal-type homeobox 2 had 70% positive predictive value. Nonetheless, cytokeratin 7 had a negative predictive value of 74%. Moreover, alpha-fetoprotein had a negative predictive value of 85.7%. Although epithelial membrane antigen showed 100% positive predictive value, human melanoma black-45 had a 100% negative predictive value in all five cases. Carcinoembryonic antigen testing on 20 cases showed positive result in 16 patients. Alcian blue staining of tumor cells in eight patients had 87.5% negative predictive value, meanwhile, periodic acid-Schiff staining of tumor cells of eight samples out of ten tested positive.

This review article gathered the literature mainly focused on colon clear cell carcinoma. The most common site of tumor was left side colon with symptoms of abdominal pain and gastrointestinal bleeding. Surgery was the preferred intervention. Pathological investigation included cytokeratin 20, cytokeratin 7, alpha-fetoprotein, carcinoembryonic antigen, caudal-type homeobox 2, and staining. However, due to rarity of colic clear cell carcinoma and small sample size, the etiology of colon clear cell carcinoma is unknown and no pathognomonic diagnostic criteria is introduced. Further clinical studies are required to shed light on this scarce type of colon cancer.