嚢胞を形成した若年者胃平滑筋芽細胞腫の1例

Juvenile Leiomyoblastoma of the Stomach with Cyst Formation, Report of a Case

要旨　胃平滑筋芽細胞腫は若年者にはまれとされるが，今回われわれは15歳の囊胞を形成した胃平滑筋芽細胞腫の1例を経験したので報告する．患者は15歳男性，主訴は心窩部痛である．胃X線検査，胃内視鏡検査，腹部超音波検査，腹部CTスキャン，血管造影検査を行った結果，胃前庭部前壁の囊胞を形成した粘膜下腫瘍と診断された．手術は術中凍結組織検査で悪性が疑われたため，幽門側胃切除術および所属リンパ節郭清（R₂）が施行された．病理学的診断は胃平滑筋芽細胞腫を得た．術後現在まで1年10か月を経過しており，再発の徴候はみられない．

　Leiomyoblastoma is a rare tumor of the stomach, especially in young adults. Including the present case, there have been only three cases in teenagers reported so far in Japan.

　A 15 year-old boy was admitted mainly with complaint of epigastralgia. By upper gastrointestinal barium studies and gastroscopic examination (Fig. 1a～c, 2), he was diagnosed to have submucosal tumor in the anterior wall of the stomach antrum. Ultrasonography and CT scan revealed cystic tumor of the stomach (Fig. 3, 4). Angiography of the celiac axis delnonstrated a tumor stain in the right upper quadrant, which was sup Plied by the right gastricartery, the gastroduodenal artery and the right gastroepiploic artery (Fig. 5).

　Distal gastrectomy with dissection of the lymph nodes in the region was performed, because suspicion of malignancy was aroused through examination of frozen section of the tumor during the surgical operation. The tumor measured 4.5×3.2×3.3cm in size. The cyst was filled with clear yellow fluid (Fig. 6). Histopathological examination of the pecimen showed leiomyoblastoma (Fig. 7a～7c). Follow-up observation during one year and eight months after the operation detected no evidence of recurrence.