Prevalence and prognostic significance of endocrine cells in colorectal adenocarcinomas.

Sporadic differentiation of endocrine cells inside adenocarcinomas of the gut (combined tumors) has been observed mainly in the stomach and less frequently in the colon. Since one or more lines of endocrine cells could be present, a wide-spectrum marker of neuroendocrine cells seems to be useful in defining the prevalence of an endocrine component in colorectal carcinomas. One hundred and fifty-eight cases of unselected colorectal adenocarcinomas were immunohistochemically evaluated on formalin fixed and paraffin embedded material, employing streptavidin-biotin-peroxidase-complex (SABC) with anti chromogranin antibodies. All samples were obtained in peripheral areas of neoplastic proliferation without necrosis or haemorrhage. Semiserial sections from each block were cut and stained with H.E., Grimelius, Masson Fontana and SABC anti chromogranin. Chromogranin positive cells were found in 22 of 158 cases (14%). In 18 cases (11.39%), scattered cells (one single cell or a few cells in each section) were located between neoplastic epithelial cells; in 4 cases (2.53%), clusters of chromogranin positive cells were found. Twelve tumors were located in the sigma-rectum, eight in the right colon and two in the left colon. According to tumor grading, five were G1 and seventeen were G2. According to tumor staging following Dukes' classification, eleven were stage B, and eleven stage C. In conclusion, no statistically significant correlations resulted between the adenocarcinoma with endocrine component and tumor location (p = 0.1 n.s.), tumor grading (p = 0.2 n.s.), and tumor staging (p = 0.1 n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)