Rectal adenocarcinoma with extensive choriocarcinomatous differentiation: Report of a rare occurrence

We report a rare case of choriocarcinomatous differentiation of tumor cells in the rectal adenocarcinoma of a 54-year-old female who presented with pain abdomen and passage of bloody stools. CT scan was suggestive of a malignant tumor in the rectum. Histologic examination of the tumor revealed a minor component of moderately differentiated adenocarcinoma that showed extensive trophoblastic differentiation. Positive immunostaining for beta-hCG of tumor cells in these areas confirmed the diagnosis. Since such tumors behave aggressively and confer bad prognosis, they constitute a distinct clinical entity of a gastrointestinal tumor.