初診後3年で腫瘍径増大が認められた胃平滑筋肉腫の1例

Gastric Leiomyosarcoma Increasing in Size Over a Period of Three Years' Observation, Report of a Case

要旨　患者は47歳，女性．集団検診（胃X線および内視鏡検査）で胃粘膜下腫瘍が指摘され，CTでも径35mmの粘膜下腫瘍が認められた．以後，1回/年，胃X線および内視鏡検査が施行された．生検診断は毎回陰性であった．3年後，胃X線およびCT検査で径48mmまでの増大が観察された．潰瘍形成も認められたが，生検診断は陰性であった．増大傾向から胃平滑筋肉腫を疑い，局所切除術を施行した．組織学的に平滑筋肉腫であることが確認された．術前，生検診断による平滑筋腫と平滑筋肉腫の鑑別には限界があり，増大傾向が認められたものは悪性を疑い，外科的治療（局所切除術）を行うべきであると考えられた．

　A gastric Leiomyosarcoma in a 47-year-old female was resected after three years' observation. The gastric tumor was detected by mass screening. Endoscopic finding revealed a submucosal tumor covered with intact mucosa. The histological examination of the biopsy specimen showed no evidence of a submucosal lesion. On initial CT scan, the tumor size was estimated at 35 mm. The patient received annual x-ray and endoscopic examination.

　Three years later, x-ray and CT scan demonstrated that the tumor had grown. Its size had increased to 48 mm. A Leiomyosarcoma was suspected because of this growth, though the biopsy specimen confirmed no malignancy. Local excision of the gastric wall including the tumor was performed. The histological examination of the resected specimen proved the tumor to be a Leiomyosarcoma.

　It is difficult to distinguish a Leiomyosarcoma from a leiomyoma before surgery. Local excision should be carried out when a submucosal tumor increases in size, even if histological evidence of malignancy is absent.