An Unusual Location of Extraosseous Ewing's Sarcoma
An 18-year-old female presented with a painful swelling in the left upper quadrant of her abdomen. She became aware of this problem 4 days before presentation. There was no history of previous illness, nor did she take any medication. Physical examination revealed a tender, painful spot and palpable mass in the left upper quadrant of the abdomen.\nBiochemistry indicated an elevated C-reactive protein value (14 mg/dl, normal <1). Tumor marker carbohydrate antigen (CA) 125 was within normal range and the lactate dehydrogenase value was not elevated.\nUltrasonographic evaluation revealed a structure in the left upper quadrant, inferior to the left kidney measuring 7 × 9.5 cm. There were calcifications visible and the study in Doppler mode revealed no apparent blood flow.\nSubsequent abdominal computed tomography (CT; fig. , fig. ) confirmed a nodular mass in the left upper quadrant measuring 6.5 × 7.5 × 10 cm. The mass was partially solid, partially cystic and had some calcifications. This mass was situated inferior to the left kidney. The spleen and pancreas were situated superior to this structure, the descending colon was posterior to this lesion and was closely related to it. The medial border of this mass was in close contact with the distal part of the transverse colon and the stomach. There was also contact with the jejunal part of the small intestine and a diffuse infiltration of the surrounding fatty tissue. There was no obvious lymphadenopathy and there were no intra-abdominal metastases.\nA CT scan of the thorax did not detect thoracic metastases. Colonoscopy was normal except for a small nodule at the cecum, which anatomopathological investigations confirmed to be a submucosal lymphoid nodule.\nExcisional surgery was planned and median laparotomy was performed. Exploration revealed that the tumor was located partially in the omentum majus and partially fixed in the retroperitoneum inferior to the spleen. There was no evidence of peritoneal or hepatic metastases during surgery, nor a connection with the small or large intestine. A wide excision of the lesion with a surrounding envelope of fatty tissue was performed. Perioperative frozen section after resection suggested the presence of a mesenchymal tumor.\nThe specimen weighted 260 g. It consisted of omental fat and peritoneum with a well-defined, encapsulated multinodular mass of 9 × 5.5 × 5.5 cm. Cross-section revealed a solid washed-out lesion with inlying yellow zones and a macroscopic aspect of necrosis.\nThe tumor was well defined with large inlying islands of necrosis. The tumor cells were monotonous and were closely packed together. The nuclei were of oval shape, irregular and had a notch. There was a moderate mitotic activity. The cytoplasm was vacuolated or lucid. Some cells were separated by connective tissue. Some tumor cells contained periodic acid-Schiff (PAS)-positive granules in the cytoplasm (fig. ).\nThe tumor that was resected during the laparotomy was positive for vimentin (fig. ) and CD99 (fig. ) (membranous) and negative for keratin, S-100, WT1, neuroendocrine marker (synaptophysin), inhibin, CD45, calretinin, CD117, CD34 and muscle markers (smooth cell actin and desmin). The morphologic and immunophenotype was consistent with ES. Molecular analysis by fluorescent in situ hybridization (FISH) confirmed an ES gene (EWS) rearrangement.\nThere were no postoperative complications. The patient was discharged from the hospital in good health on the 4th postoperative day. A whole-body positron emission tomography (PET)/CT scan was performed 4 weeks after surgery, which revealed no evidence for hypermetabolic activity.\nTwo months after treatment, the patient underwent laparoscopic resection of the left adnexa for cryopreservation. During this laparoscopy, 2 lesions of endometriosis were discovered and excised. The adjuvant chemotherapy regimen consisted of a 3-drug regimen including vincristine, ifosfamide and doxorubicin. There were 8 cycles planned every 3 weeks. After the first cycle, the patient had neutropenic fever which necessitated intravenous antibiotics. The subsequent second cycle was given in combination with neurokinine-1 receptor antagonist and granulocyte colony-stimulating factor (pegfilgrastim).\nA CT scan of the thorax and abdomen 3 months after surgery revealed no recurrence.\nAfter the third cycle, the patient had neutropenic fever and severe thrombopenia. The patient received intravenous antibiotics and a pool of thrombocytes. There were no other problems reported during the last 5 cycles of chemotherapy. The 6th cycle was one with a dose reduction of doxorubicin and ifosfamide (80%). During this regimen, she received intramuscular injections of luteinizing hormone releasing hormone to protect the right ovary.\nThe PET/CT scan performed 6 months after chemotherapy revealed no evidence for local, lymphatic or hematogenic recurrence. Ultrasound evaluation of the abdomen and X-ray of the chest revealed no recurrence 14 months after surgery.