Adenocarcinoma of the Sigmoid Colon with Prominent Rhabdoid Features: A Case Report

ABSTRACT

Colorectal adenocarcinoma with rhabdoid features is extremely rare and only two cases have been previously reported. We report here on a case of colorectal adenocarcinoma with prominent rhabdoid features in a 69-year-old female. The specimen was an ulcerative mass from the sigmoid colon, and it measured 3.5x3 cm. Microscopic examination of the tumor showed mostly rhabdoid cells that had eccentrically located large nuclei and foci of glandular formation. A transitional area from the poorly differentiated adenocarcinoma to the rhabdoid tumor was also noted. Immunohistochemical studies showed strong reactivity of the glandular forming cells for pan-cytokeratin, and the cells were occasionally positive for vimentin. The cells with rhabdoid features were diffusely positive for vimentin and focally positive for pan-cytokeratin. These results suggested that the cells with rhabdoid features originated from dedifferentiated primary adenocarcinoma. Since colorectal adenocarcinoma with rhabdoid features is highly aggressive and unresponsive to conventional therapy, making the preoperative diagnosis is important to facilitate the treatment.