A challenging diagnosis of mesenchymal neoplasm of the colon: colonic dedifferentiated liposarcoma with lymph node metastases-a case report and review of the literature.

We report a case of primitive colonic dedifferentiated liposarcoma along with lymph node metastases. The patient's clinical, radiologic, surgical, and histologic data were reviewed, as well as the literature on colonic dedifferentiated liposarcoma with a focus on the incidence of lymph node metastasis in gastrointestinal sarcomas and on the differential diagnosis with other spindle cell tumors in the gastrointestinal tract. A 53-year-old man was referred to our hospital with a 3 year-history of pain on the right back that was refractory to drugs. He performed an abdominal computed tomography scan which revealed a colonic wall thickening in the hepatic flexure and a few serosal nodularities. With these findings, the patient underwent an extended right hemicolectomy. On histopathologic examination, it turned out to be a colonic dedifferentiated liposarcoma with lymph node metastases. The present case was a challenging diagnosis both at presurgical and histopathological level because it strongly mimicked a colonic adenocarcinoma. This was due to non-specific clinical and radiological presentation, to the non-characteristic histologic morphology and to the misleading presence of lymph node metastases. Malignant stromal tumors of the gastrointestinal tract beyond gist are fairly rare entities. Colonic dedifferentiated liposarcoma must be kept in mind and must be considered in the differential diagnosis of gastrointestinal tumors.