手に発生した未熟神経外胚葉性腫瘍の1例

Primitive Neuroectodermal Tumor of the Hand. Case Report

　手に発生した未熟神経外胚葉性腫瘍（PNET）の極めて稀な1例を報告する．症例は18歳の男性で，主訴は右手小指球部の腫瘤である．腫瘤は2年の経過で直径7cmになっていた．生検による病理組織検査で小円形細胞の増殖とロゼット様配列を認めた．免疫染色でCD99が陽性であり，PNETと診断した．術前化学・放射線療法により腫瘍は著明に縮小し，小指指列切断術を施行した．術後10カ月において局所再発，遠隔転移を認めない．手に発生したPNETを補助療法と指列切断で治療し良好な結果を得た．

　Background：Primitive neuroectodermal tumor (PNET) of the hand is extremely rare. We report a case of PNET in the hypothenar eminence.　Case report：An 18-year-old man with a hard, elastic mass on the ulnar aspect of his right hand came to our hospital because the mass had been diagnosed as a ganglion at another institution and had gradually enlarged to a maximum diameter of 7 cm over a 2-year period. An incisional biopsy was performed, and histological examination of the specimen revealed a tumor composed of small blue round cells, some of which had formed rosettes. Immunostaining for CD99 was positive, and the tumor was diagnosed as a PNET. After preoperative chemotherapy and radiotherapy, ray amputation of the little finger was performed and followed by postoperative chemotherapy. There has been no evidence of tumor recurrence as of 10 months after surgery.