Undifferentiated pleomorphic sarcoma (UPS) is the most common sarcoma that appears in older patients, usually in the extremities and the retroperitoneum. Other locations are rare. By definition, in UPS, although the malignant cells tend to appear fibroblastic or myofibroblastic, they should not show differentiation towards a more specific line of differentiation. In this sense, we report the case of an 80-year-old patient with an initial clinical diagnosis of a locally advanced colonic neoplasm that was later confirmed as a primary mesenteric UPS. Primary mesenteric UPS are extremely rare with less than 20 cases reported. We also review the pathologic and radiologic diagnostic criteria and the natural history of these tumours.

Colitis-associated colorectal carcinoma (CAC) occurs in inflammatory bowel disease (IBD) because of the “chronic inflammation-dysplasia-cancer” carcinogenesis pathway characterized by p53 alterations in the early stages. Recently, gastric metaplasia (GM) has been described as the initial event of the serrated colorectal cancer (CRC) process, resulting from chronic stress on the colon mucosa. The aim of the study is to characterize CAC analyzing p53 alterations and microsatellite instability (MSI) to explore their relationship with GM using a series of CRC and the adjacent intestinal mucosa. Immunohistochemistry was performed to assess p53 alterations, MSI and MUC5AC expression as a surrogate for GM. The p53 mut-pattern was found in more than half of the CAC, most frequently stable (MSS) and MUC5AC negative. Only six tumors were unstable (MSI-H), being with p53 wt-pattern (p = 0.010) and MUC5AC positive (p = 0.005). MUC5AC staining was more frequently observed in intestinal mucosa, inflamed or with chronic changes, than in CAC, especially in those with p53 wt-pattern and MSS. Based on our results, we conclude that, as in the serrated pathway of CRC, in IBD GM occurs in inflamed mucosa, persists in those with chronic changes and disappears with the acquisition of p53 mutations.

Synovial sarcoma (SS) is a high-grade, rare variant of soft tissue sarcoma (STS). The biphasic subtype is less common than the monophasic subtype. SS is very common around joint cavities in the extremities, but can be present elsewhere in the body. Tumor staging and therapeutic management are usually clear for a localized disease, but the proper management at the metastatic stage can be unclear. According to the literature, the histologic presence of an SS tumor thrombus affects tumor staging, making it unclear whether the tumor stage corresponds to localized or metastatic disease. An intravascular SS tumor exhibiting high metastatic potential is a rare finding that warrants thorough investigation.A 49-year-old woman presented with a biphasic SS intravascular tumor of the left inguinal area with femoral vessels involvement. Ten cases of intravascular SS have been reported in the literature and contain little information regarding the proper management of a local metastatic disease. Ours is a rare case of SS with an intravascular tumor occupying the femoral-iliac vein (as seen in metastatic disease) that has been treated as a local disease with a multidisciplinary therapeutic approach. As a result, our patient has been disease-free for two years and, during that time, has achieved an acceptable quality of life.We discuss the pertinent clinical findings of this rare tumor and review the literature of tumor thrombus by SS. We also present the multidisciplinary therapeutic approach realized and the history of this disease.