Objective: Inflammatory myofibroblastic tumor (IMT) is a very rare tumor of the colon in which the diagnosis is especially based on immunohistochemistry. In the colon, we report the 25th case of IMT. Method: Case presentation Results: We report the case of a 56-year old male who presented with symptoms suggesting colon cancer. A 20 mm protruded tumor was endoscopically described in the ascending colon. Right hemicolectomy was performed. Macroscopically the tumor was well defined, covered by normal mucosa with a central depressed area, suggesting a GIST (Gastrointestinal Stromal Tumor). Microscopically spindle cells with fascicular arrangement admixed with mononuclear leukocytes were observed. The tumor cells expressed Vimentin, SMA, Desmin and ALK and were CD34 and CD117 negative. Intense angiogenesis and CD117 expression in the endothelial cells were also observed. Conclusion: In the IMT of the colon, clinical endoscopic and gross feature can imitate a carcinoma or a GIST. The IHC pattern of IMT can offer informations about its histogenesis. Based on the immunophenotype, we hypothesize that this tumor seems to occur from the the pluripotent stromal cells, CD34 positive which can be either differentiated in the interstitial cells of Cajal (telocytes), which are also CD34 positive or, during differentiation, can loss CD34 positivity. Objective: Determining the fraction of tumor cells in colon carcinoma samples analyzed for KRAS mutation is important for choosing the proper testing modality. However, when asked to determine tumor cell fraction in tissue samples, different pathologists give considerably different estimations, possibly leading to erroneous interpretation of KRAS mutation analysis results and poor treatment choices. Method: We developed a free, easy to use computer program that estimates tumor cell fraction on colon carcinoma slides that are immune-stained with anti-cytokeratin antibody. Sixty samples were evaluated by the program and results were compared to actual measurement of tumor fraction. Results: The tumor cell fraction estimated by the computer program showed highly significant correlation with the actual measurements (R=0.64, p<0.001). Additionally, we found that a short calibration step prior to beginning the computer estimation increased the accuracy of the results. In four cases (7 %) there was some discrepancy between the computer estimation and the actual measurements, however, this was attributed to lower quality immunohistochemical staining. Conclusion: In conclusion, we believe that this program can be used for standardizing the evaluation of tumor cell fraction in colon carcinoma, and that its use might aid in making better diagnosis and treatment choices for these patients.