A 0.8-mm Depressed Adenoma of the Colon with High-Grade Dysplasia

Flat and depressed cancers of the colon have now been recognized in several centers throughout the world. We report here a case of a 0.8-mm depressed adenoma with high-grade dysplasia in a 70-year-old man. We believe this to be the smallest adenoma ever reported, and unusually (for a small lesion) it was positive for the K-ras mutation.

References

• 1 Muto T, Kamiya J, Sawada T, et al. Small “flat adenoma” of the large bowel, with special reference to its clinicopathologic features.  Dis Colon Rectum. 1985;  28 847-851
• 2 Fujii T, Rembacken B J, Dixon M F, et al. Flat adenomas in the United Kingdom: are treatable cancers being missed?.  Endoscopy. 1998;  30 437-443
• 3 Stolte M, Bethke B. Colorectal mini-de novo carcinoma: a reality in Germany too.  Endoscopy. 1995;  27 286-290
• 4 Muto T, Nagawa H, Watanabe T, et al. Colorectal carcinogenesis: historical review.  Dis Colon Rectum. 1997;  40 (Suppl. 10) S80-S85
• 5 Kuramoto S, Oohara T. Flat early cancers of the large intestine.  Cancer. 1989;  64 950-955
• 6 Kudo S. Endoscopic mucosal resection of flat and depressed types of early colorectal cancer.  Endoscopy. 1993;  25 455-461
• 7 Wada R, Matsukuma S, Abe H, et al. Histopathological studies of superficial-type early colorectal carcinoma.  Cancer. 1996;  77 44-50
• 8 Jaramillo E, Watanabe M, Slezak P, Rubio C. Flat neoplastic lesions of the colon and rectum detected by high-resolution video endoscopy and chromoscopy.  Gastrointest Endosc. 1995;  42 114-122
• 9 Togashi K, Konishi F, Ishizuka T, et al. Efficacy of magnifying endoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps of the large bowel.  Dis Colon Rectum. 1999;  42 1602-1608
• 10 Vogelstein B, Fearon E R, Hamilton S R, et al. Genetic alterations during colorectal-tumor development.  N Engl J Med. 1988;  319 525-532
• 11 Minamoto T, Sawaguchi K, Mai M, et al. Infrequent K-ras activation in superficial-type (flat) colorectal adenomas and adenocarcinomas.  Cancer Res. 1994;  54 2841-2844