The automatic, non-invasive diagnosis of the abdominal tumors is an important issue in nowadays research. We develop computerized methods for this purpose, based on ultrasound images. We previously defined the textural model of these tumors, consisting of the relevant textural features that best characterize them and of their specific values. In this work, we developed a texture analysis method based on the Textural Microstructure Cooccurrence Matrix (TMCM) of order two and three, and we assessed its role in abdominal tumor recognition. We used feature selection methods in order to determine the most important features and to improve the classification process. We assessed the classification performance using the old and the newly resulted textural features. For the experiments, we considered the hepatocellular carcinoma (HCC), the most frequent malignant liver tumor, versus the cirrhotic parenchyma on which it evolved, as well as the colorectal tumors versus the Inflammatory Bowel Diseases (IBD).