十二指腸原発平滑筋芽細胞腫の1例

Leiomyoblastoma of the Duodenum, Report of a Case

要旨　患者は61歳の女性で心窩部痛にて来院．胃十二指腸造影にて，十二指腸下行脚外側に大きな深掘れ潰瘍を認めた．内視鏡検査でも同部に洞窟様の深い潰瘍を認めたが，周囲の粘膜には異常はなかった．腹部血管造影では十二指腸枝は拡張し，その領域に腫瘍血管の著明な増生と腫瘍濃染像を認めた．以上より十二指腸平滑筋肉腫と診断し，リンパ節郭清を伴う膵頭十二指腸切除および横行結腸部分切除術を施行した．腫瘍は80×90×50mmで，割面は灰白色充実性で，所々に出血，壊死を認めた．病理組織所見では，腫瘍の大部分は類円形の核を有し，好酸性の胞体から成る上皮様細胞で占められており，leiomyoblastomaと診断された．

　A 61 year-old woman was admitted to our hospital complaining of epigastralgia. Upper gastrointestinal x-ray series showed a giant ulcer on the 2nd portion of the duodenum (Fig. 1 a, b). Duodenoscopy also revealed a deep, cave-like ulcer on the same portion. Biopsy specimens showed this was not malignant (Fig. 2). A large tumor was recognized in the duodenum on CT-scan (Fig. 3). Superselective gastrointestinal angiography showed a hypervascular lesion with marked neovascularity, dilated feeding arteries and an irregular tumor stain in the duodenum (Fig. 4 a, b). Before operation, this lesion was diagnosed as leiomyosarcoma of the duodenum.

　Pancreaticoduodenectomy and partial transverse colectomy were performed. Resected specimen showed globular tumor, 80×90×50 mm in size. Fibrous capsule and a giant deep ulcer were recognized on the duodenal mucosa (Fig. 5 a). Bleeding and necrotic degeneration were found here and there on the grayish and solid cut surface (Fig. 5 b, c). Histologically most of this tumor was composed of cells with vacuolated round epithelioid cells with eosinophilic cytoplasm, partly bizarre polygonal cells with vacuolated cytoplasm or spindle cells (Fig. 6 a-d), and was diagnosed as malignant leiomyoblastoma because of lymph node metastasis. The patient is still alive and well 17 months after surgery.

　In Japanese literature leiomyoblastoma of the duoednum is rare (only nine cases have been reported) and has had a greater tendency to be malignant than has leiomyoblastoma of the stomach (Table 1).