Atypical Mitosis in Gastric Intestinal Metaplasia in Japanese Patients

Abstract

The characteristics of the mitotic figures occurring in intestinal metaplasia of the gastric mucosa were investigated in 50 consecutive gastrectomy specimens. The specimens contained, in addition, early gastric cancer of intestinal type (n = 38) or of diffuse type (n = 12). One hundred or more consecutive mitoses/specimen were studied by high‐power microscopy (× 1000). Of the 5,140 mitoses, 1,030 (i.e. 20.0%, range 8–34%) were considered as atypical according to a previous classification. The presence of atypical mitosis was not influenced by the gender or age of the patient, or the histological type of the tumor present in the specimen. Studies of gastrectomy specimens from Swedish patients with early gastric cancer showed a much lower frequency of mitotic figures/specimen and occasional atypical mitosis. The high frequency of atypical mitosis in intestinal metaplasia in the gastric mucosa of Japanese nationals may mirror a profound genetic instability in that mucosa, and suggests that intestinal metaplasia with atypical mitosis may be a precancerous lesion in the Japanese.

Benign reactive lesion with atypical mitosis: New example of an old story

“…However, demonstrating atypical mitotic figures in a benign reactive lesion is not something new, but is rare finding in both experimental and surgical pathology related to inflammatory or regenerative processes [1][2][3][4][5][6][7][8]. One may argue that some of above mentioned chronic pathological processes, for example, long standing ulcerative colitis [4] and gastric intestinal metaplasia [5], are associated with malignant potential. It is true that the role of ulcerative colitis or intestinal metaplasia as pre-neoplastic lesion is well established, associating with various genetic alterations or chromosomal instability [12,13].…”

“…After over one century, a general consensus has been reached in the surgical pathology society, stating that an atypical mitotic figure may indicate a malignant process while it can also be seen in benign lesions. For example, atypical mitotic figures can be occasionally found in granulation tissue following ionizing-radiation exposur, ischemic colitis, long standing ulcerative colitis, gastric intestinal metaplasia, endometrium associated with chorionic tissue effect, benign cutaneous lesions induced by taxane therapy, and abnormal but non-neoplastic astrocytes [2][3][4][5][6][7][8]. Herein, a rare case of ischemic fasciitis, also named as atypical decubital fibroplasia, is reported, which shows typical clinical and histological features, except that atypical mitosis is evident.…”