Ewing’s sarcoma/primitive neuroectodermal tumor (ES/PNET) of the small bowel: a rare cause of intestinal obstruction

Abstract

Dear Editor: Ewing’s sarcoma/primitive neuroectodermal tumor (ES/PNET) is the second most common primary bone tumor in pediatric patients, accounting for approximately 1.1% of childhood cancers in Korea. Extraskeletal or extraosseous ES/PNET, reported to develop in tissues derived from the neural crest, usually develops in the soft tissue of the lower extremities, paravertebral region, and pelvis in children and adolescents. ES/PNETof the small bowel is extremely rare, with only two such cases reported in young patients to date to our knowledge. The present study details a case of extraskeletal ES/PNET of the small bowel in a 63-year-old male Korean. A 63 year-old man was admitted experiencing progressive right low quadrant (RLQ) abdominal pain with distension in October 2005. Since January 2005, the patient had undergone treatment for non-small cell lung cancer (NSCLC) at the Center for Lung Cancer, National Cancer Center, Korea. In staging workups at diagnosis, abdominal CT scans showed three abdominal masses comprising a 12.0×9.0-cm mass in the right adrenal gland, a 7.0×7.0-cm mass in the left adrenal gland and a 5.6×2.7-cm mass in the RLQ. Radiology-based diagnosis of the abdominal masses suggested that the primary lung cancer had metastasized to both adrenal glands and mesenteric lymph nodes. A colonoscopy was performed to rule out colon cancer, and the results showed no abnormal findings in the entire large bowel and terminal ileum. The patient commenced chemotherapy on January 26, 2005. Three regimens were used; six cycles of Gemcitabine, Vinorelbine, and Cisplatin from January to June, three cycles of Docetaxel from June to August, and one cycle of Gefitinib in October. Surveillance computed tomography (CT) scans of the abdomen and pelvic cavity performed on November 4th showed that both adrenal masses had become necrotic without a significant change in size, the RLQ mass had increased to 18.0×12.5×11.0 cm, and there were several new enlarged mesenteric lymph nodes near the RLQ mass. Abdominal distension with pain had developed so severely by the end of October 2005 that the patient was referred to the Center for Colorectal Cancer to undergo surgical symptomatic palliation. A right hemicolectomy with a segmental resection of the jejunum was performed. The resected tumor was multinodular, solid, and 18.0 cm in the largest diameter and showed focal necrosis and hemorrhage. The tumor impinged on the terminal ileum and jejunum, invading the enteric wall extending to the mucosa and obliterating the lumen of the terminal ileum. The ascending colon was severely D.-W. Kim . H. Chang . J. Jeong . S.-B. Lim (*) . H. Choi . S.-Y. Jeong . J.-G. Park Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, 809 madu-1-dong, ilsandong-gu, Goyang-si, Gyeonggi-do, 410-769, Repubic of Korea e-mail: sblim68@ncc.re.kr Tel.: +82-31-9202486 Fax: +82-31-9201959