胃肉腫の細胞診

Cytologic Diagnosis of Sarcoma of the Stomach

　胃肉腫は胃悪性腫瘍中約0.5～3％（ほぼ2％）前後と言われており，その頻度はかなり低い．しかし，その臨床症状が胃癌とほとんど相違がないために，以前は胃癌の診断で手術され，その切除標本や剖検の病理組織学的検索により胃肉腫と確診される場合が多く，報告例も多くがそのような症例についてであり，この疾患を術前診断の面より論じた報告は極めて少なかった．しかし過去十数年間のX線，内視鏡，生検，細胞診などの診断学の進歩により，診断学各分野でのこの疾患に関する知見もしだいに報告されるようになった．

　このような胃肉腫の術前診断の可能性を最初に報告したものが細胞診の分野であった．すなわち1958年津田，信田¹⁾による“手術前細胞学的に診断し得た胃細網肉腫の一例”の報告を嚆矢として，山形²⁾，山田³⁾，綿貫⁴⁾，信田^5)～7)，春日井⁸⁾，池口⁹⁾らの細胞診研究者による術前診断可能例の報告が続き，悪性リンパ腫の細胞学的特徴もしだいに明確にされてきた．

　Nineteen case of sarcoma of the stomach were examined cytologically during the last 25 years in Department of Surgery in Juntendo University and Dokkyo University Hospital. Cytologic features of malignant cells in sarcoma of the stomach are described in this paper. The characteristics of malignant cells of the sarcoma are very different from those of carcinoma in the stomach.

　Malignant cells from reticulum cell sarcoma showed:

　(1) Cell arrangement is in isolated and scattered form.

　(2) Cell membrane is well preserved.

　(3) Cytoplasma is stained darkly basophilic by MG-Giemsa staining. Peculiar protrusion of cytoplasma is observed in some cases.

　(4) Small and many vacuola are seen in the cytoplasma in some cases.

　(5) Nuclear membrane is usually not so thickened.

　(6) Nuclear chromatin shows fine granular type.

　(7) These malignant cells are usually large in their size.

　(8) Abnormal mitotic figures are observed in some cases.

　These characteristics are very different from those of gastric cancer cells. Differentiation of malignant cell of reticulum cell sarcoma from gastric cancer cells is not difficult.

　Malignant cells in lymphocytic sarcoma are smaller in size and cytoplasma is scant.

　Leiomyosarcoma cells show characteristics as follows:

　(1) Large, abundant, long cytoplasma and irregularly shaped cells are observed.

　(2) Nuclei are round or oval and rather large.

　(3) Overlapping of cells is not observed.

　In case of Hodgkin's disease of the stomach, the Hodgkin's cell with mirror-image and Reed-Sternberg's polynuclear giant cells are observed.

　The result of cytologic examination was positive in 14 cases out of 15 malignant lymphoma (positive result was 93.3%). However, the result for leiomyosarcoma was not so significant (33.3%).

　Effectiveness of cytologic examination for the diagnosis of sarcoma of the stomach is emphasized.