Ewing sarcoma most commonly arises in bones but rarely presents in extraskeletal locations. We report one such case arising from the jejunum.

A 67-year-old woman presented with acute-onset, right lower quadrant pain. Computed tomography results showed a large mass within the midjejunum with pneumoperitoneum. Surgical excision was performed, and an extraskeletal Ewing sarcoma of the jejunum was suspected histologically. The diagnosis was confirmed with fluorescence in situ hybridization studies.

This case emphasizes the importance of recognizing this rare presentation in the small intestine to broaden the differential diagnosis of adult intraabdominal tumors.

Ewing Sarcoma is a highly lethal undifferentiated tumor of bone. ES is a small round cell tumor with etiological and characteristic chromosomal translocations between TET/FET (TLS/FUS, EWSR1, and TAF15) and ETS (E26 transformation-specific) family genes. Generally, therapeutic approach for metastatic Ewing Sarcoma includes both local (surgery and radiotherapy) and systemic (chemotherapy) disease control with an overall cure rate of 20%. For extra-osseous tumors, the most common primary sites of disease are trunk, extremities, head and neck, retroperitoneum. Among other sites, Ewing Sarcoma/PNET may also rarely arise in colon and rectum. Even if colonic Ewing Sarcoma/PNET have been previously reported in 5 cases, none of those reports came from right side of the colon. In this article, we report the first case of right-sided Ewing Sarcoma with synchronous liver metastases completely responding to first line chemotherapy. Furthermore, we provide a systematic qualitative review of the current literature on adult colorectal Ewing Sarcoma using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Sarcomas are malignant tumors that arise from mesenchymal tissue at any of the body sites. They incorporate the wide category of GISTs and are classified in various histological types. Histological grading is another indicator of the degree of malignancy, the probability of distant metastases, and survival but remains a poor definition of local recurrence.

The size and depth of invasion are the most important prognostic factors. Since they grow within the intestinal wall, the symptoms are usually few or late, leading to delays in diagnosis. Most common signs are rectal bleeding, abdominal or anal pain, diarrhea, tenesmus and weight loss. The diagnostic and staging protocol of stromal tumors of the rectum includes mainly endoscopic surveillance, computed tomography, and magnetic resonance imaging. Therefore, rectum sarcoma (RS) consists one of the most biologically virulent cancers and is difficult to cure by conventional procedures. The treatment is primarily surgical, where possible, and should guarantee complete clearance of the tumor, which often requires an aggressive approach. Unfortunately, the minority of patients is eligible to undergo surgical intervention. In addition, surgical removal of RS does not necessarily indicate a patient's long-term recovery. Alternative therapies, such as radio- and chemotherapy, proved insufficient. Elucidation of its molecular basis may prove useful in developing and identifying prognostic biomarkers.