소장의 장간막에 발생한 말초성 신경외배엽 종양

초록

Peripheral primitive neuroectodermal tumor (pPNET) may occur anywhere in the body. The primary sites of pPNET were the chest wall, pelvis, retroperitoneum. abdomen, limb, neck in descending frequency. Isolated cases of pPNET have been reported in various visceral site, including the pancreas, heart, kidney, ovary, uterus, testis, urinary bladder, parotid gland and mesentery. Only one case of pPNET of the mesentery with perforation at onset similar to our case was reported. A case of pPNET of the small bowel mesentery presented with tumor rupture and showing uncommon histologic finding is reported. A 23-year-old man was admitted to our hospital because of acute severe abdominal pain. Abdominal CT revealed a large solid and cystic, oval shaped mass, measuring 11.0x6.0cm, at pelvic cavity. At emergency surgery a large ruptured mass was noted in the jejunal mesenteric region, 1cm apart from the Treitz ligament. Partially the tumor was tightly adhered to the jejunal wall. Segmental resection of small intestine and omentectomy were performed. The resected tumor measuring 12.0x8.0x7.5cm was located in the mesentery of jejunum. Rupture was seen in the surface of tumor. The cut surface reveals whitish-pink solid appearance with foci of hemorrhage, extensive necrosis and myxoid change. The border was irregular and the tumor directly invaded into the wall of jujunum, resulting in focal mucosal erosion. Histologically the tumor was composed of sheets of undifferentiated small round cells forming Homer-Wright rosettes and showed areas of osteoid and bone formation. Some spindle-shaped cells demonstrated perivascular pseudorosettes. The tumor cells were immunoreactive for CD99(IMIC2), CD57, neuron-specific enolase and vimentin. To the authors' knowledge this is the first documentation of pPNET with osteoid and bone formation of the small bowel mesentery.