多発性胃平滑筋腫の1例とその文献的考察

A Case of Multiple Leiomyoma of the Stomach with Special Reference to the Literature

　最近胃のX線及び内視鏡診断技術の進歩に伴い，胃粘膜下腫瘍の発見ならびに鑑別診断は非常に向上して，その報告例も数多くなり，稀有なものとはいえなくなっている．

　特に胃平滑筋腫は，胃に発生する良性腫瘍のうちではポリープに次いでその頻度が高いが，その大多数が単発例であり，多発例は比較的稀である，これに反して悪性リンパ腫は一般に多発することが多いため，臨床上多発性粘模下腫瘍を認めた場合に，われわれはまず悪性リンパ腫を考えるのが通例である．稀に多発せる平滑筋腫に遭遇した場合に，治療方針決定上この両者の鑑別診断が，重要であるにもかかわらず，甚だ困難なことが多い．

　A 50-year-old woman, free from any subjective symptoms, visited our hospital because of an abnormal shadow in the stomach detected at a mass screening. Roentgenologic examination of the stomach revealed two round and well-defined shadow defects on the posterior wall of the cardiac region. Endoscopy showed three almost hemispherical protrusions here. Their surface was smooth and the color was the same as the surrounding mucosa. There was no ulceration. The mucosal folds around the tumors seemed to course away from them. Biopsy of the mucosal surface showed no abnormality. The most likely diagnosis then was leiomyomas of the stomach, but we decided to perform laparotomy because we were unable to rule out malignancy on account of multiplicity of the tumors.

　As we were able to arrive at a diagnosis of leiomyoma during the operation on examining rapid frozen sections, we performed wedge-like partial resection of the stomach including the neoplasms. The resected specimen showed three tumors in the submucosal layer. measuring 8×6×5 mm, 5×4×4 mm and 1×1×1 mm, respectively. Histologically they were all leiomyomas.

　Of benign tumors originating in the stomach, leiomyoma ranks second to polyp in frequecy, but most of it are solitary. Multiple cases are relatively rare. In contrast to this, malignant lymphoma of the stomach is noted for its multiplicity. It would be quite natural for us to think of malignant lymphoma when we came across multiple submucosal tumors of the stomach. On encountering multiple leiomyomas seldom seen as in our accurate case, differential diagnosis between the two neoplasms would play an important role in deciding the principle of further treatment.