The Differentiation of Noninvasive and Invasive Carcinoma Arising in Intestinal Polyp
EDWIN R. FISHER, M.D.
Department of Pathology
RUPERT B. TURNBULL, M.D.
Department of Surgery
ONE of the most perplexing problems confronting the surgical pathologist is the diagnosis of carcinoma in intestinal polyp. It is important to the surgeon that the pathologist not only establish the presence of carcinoma but also the type. Therapy, as outlined in another article,1 depends upon complete diagnosis, since certain carcinomas arising in polyp may be treated locally without minimizing the chances of cancer cure.
In designating the type of carcinoma arising in polyp, we have used descriptive terms rather than numerical grades (table). Three types are recognized: (1) carcinoma in situ in which there is anaplasia and irregularity of the glandular epithelium without disruption of the basement membrane or invasion of the lamina propria (figs, 1a and b); (2) superficial carcinoma characterized by the changes mentioned previously as well as noticeable reduplication of lumina and the presence of tumor masses lying free in the lamina propria but without invasion of the muscularis mucosa (fig. 2); (3) invasive carcinoma which reveals, in addition, invasion of the muscularis mucosa with access of malignant cells to the lymphatics and vessels of the sub-mucosa of the bowel (fig. 3a). Carcinomas without evidence of benign polyp in their structure are classified as polypoid carcinoma and do not appear in this classification. The differentiation of superficial or noninvasive carcinoma from the invasive type is, at times, difficult since the demonstration of invasion of the muscularis mucosa may be overlooked or misinterpreted because of incomplete sectioning or poor orientation of the sections or because the muscularis. . .