To investigate the process of carcinogenesis in gastric cancer, we studied the histological features and cell kinetics in the gastric mucosa of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-treated rats. Samples of gastric mucosa from both MNNG-treated and control rats were histologically examined by staining with nucleolar argylophilic nonhistone (AgNOR) proteins, and their ornithine decarboxylase (ODC) activity was determined every 2 months for 10 months. In 40% of the MNNG-treated rats, atrophy of the gastric mucosa was observed after 2 months, followed by adenomatous proliferation. More AgNOR-positive granules were found in the pyloric glands than in the fundic glands, and the total number of positive granules increased over time. Cancerous and hyperplastic lesions preferentially developed in the pyloric glands and showed significantly more AgNOR-positive granules than the normal mucosa. After 6 months the ODC activity in the MNNG-treated rats was significantly higher than that in the control rats. These results thus suggest that the pyloric glands have a high growth activity, while in addition, adenomatous proliferation is a characteristic pathological feature of precancerous lesions in the stomach in MNNG-treated rats.

Bronchogenic cysts usually develop in the intrathoracic or intramediastinal area, but those originating in retroperitoneal cavity are extremely rare. Eight cases of abdominal bronchogenic cyst have been reported in Japan (five cases of retroperitoneal cyst and three cases of intraperitoneal cyst). A 26-year-old male was admitted to the hospital because of a left lateral abdominal pain. Upper gastro-intestinal series, Ultrasonography, Computed tomography and Magnetic resonance imaging revealed an adrenal tumor or retroperitoneal hematoma. A operation was performed, because a possible malignancy could not be ruled out. The tumor was adjacent to the surface of the left kidney and left adrenal gland, and a 5.5×4.0×4.0 cm elastic soft multicystic tumor with smooth surface. The pathological diagnosis was bronchogenic cyst, because it was approved mucosal epithelium, smooth muscle fibers and cartilage tissue. The disease presents very difficulty in preoperative diagnosis. It appears in a low frequency, but we should entertain it as a probable differential diagnosis. We describe the present case with discussion of eight cases reported in Japan.

We encountered a case of endobronchial hamartoma in the right lower lobe bronchus. The patient was a 59-year-old man who consulted a nearby clinic with a chief complaint of pneumonic symptoms. A polypoid mass was detected in the right lower lobe bronchus on detailed examination. A malignant submucosal tumor was suspected, and the patient was referred to our department for surgical treatment. Since malignancy was suspected and severe secondary changes such as apnematosis in the lower lobe and pneumonia were present, right lower lobectomy was performed. The postoperative histopathological diagnosis of the condition was non-cartilaginous hamartoma. Generally, tumor resection such as endoscopic resection is sufficient in treating this condition. However, lobectomy is inevitable in some cases because of the difficulty of preoperative diagnosis and prolonged distal apneumatosis. Bronchoscopic examination is recommended in cases with pneumonic symptoms to facilitate early detection, and improvement of the biopsy technicue is awaited.

残胃癌19例の腫瘍部および非腫瘍部3か所の計4か所についてargylophilic nucleolar organizer regions (以下, AgNORと略記) 染色を行い, 細胞増殖活1生について検討を行った.吻合部 (胃腸吻合部) および縫合部 (吻合部以外の切除断端の埋め込み部) のAgNOR数は口側断端部に比べ有意に高値を示し, 十二指腸液の胃内への逆流による増殖活性の亢進が示唆された.腺窩上皮の過形成, 粘膜下侵入腺および嚢胞腺などの組織学的変化は術後年数の長いBillroth II法再建群の吻合部, 縫合部に顕著に認められた.AgNOR数はこれらの組織において高値を示し, 十二指腸液逆流による組織破壊に対する細胞増殖活性の上昇が示唆された.以上より残胃吻合部, 縫合部粘膜の細胞増殖活性の上昇が認められ, 特に腺窩上皮の過形成, 粘膜下侵入腺および嚢胞腺などの組織学的変化の細胞増殖活性は高く, 残胃断端部癌の発生との関連性が示唆された.

1984年から1993年 (後期) の教室の多発胃癌の頻度は9.7%で, 1974年から1983年 (前期) の4.7%より有意 (p<0.05) に増加した. 後期の症例中多発進行癌3例を除く多発胃癌106例の副病巣は, 同期間の単発早期胃癌 (n=455) に比べ, IIa型癌, 分化型癌, m癌の比率が有意 (p<0.01) に高く, 腫瘍長径は10mm以下の病巣が最も多かった. 術前診断率は, 副病巣全体 (n=106) で71.7%, 微小癌巣 (n=15) で13.3%, 腺腫 (n=13) で33.3%であった. 同期間の残胃の癌は21例で, 初回手術後10年以上経過した例が多かった. また, 多発胃癌の他臓器癌合併頻度は, 単発胃癌に比べて有意 (p<0.05) に高かった.以上, 術前見落としやすい病巣は15mm以下のm癌と腺腫であり, 残胃予定部位を内視鏡により十分に観察することが重要である. また, 残胃の癌, 他臓器癌を念頭にいれた長期のフォローアップが必要と思われた.

The expression of the CD44 molecule was investigated in 111 cases of a resected gastric cancer, and also in 5 gastric cancer cell lines. An immunohistochemical study using frozen sections revealed that the mucosal lymphocytes and the pyloric glands deep in the normal mucosa reacted to the anti-CD44 monoclonal antibody. 54 cases (48.6%) were stained on the cell surface involving the intercellular aspect. Well-differentiated cancer showed the highest frequency of CD44 expression, among the various histological types. Moreover, cases with extensive vascular invasion frequently expressed CD44 (75%) and CD44-positive cases had a significantly higher rate of metastasis to the liver than did negative cases. Flowcytometric analysis revealed expression of CD44 on the cell surface in one of 5 examined cell lines.