A Case of Undifferentiated Carcinoma of the Ascending Colon Presenting with Humoral Hypercalcemia

Abstract

We report a case of humoral hypercalcemia of malignancy (HHM) associated with undifferentiated colon can-cer. A 41-year-old man admitted for acute abdomen and undergoing right colectomy was found to have a hard mass in the ascending colon diagnosed immunohistochemically as undifferentiated carcinoma. Postoperative CT findings showed multiple liver metastases. Hypercalcemia was observed on postoperative day (POD) 80 and diagnosed as HHM associated with undifferentiated colon cancer. Bisphosphonate treatment normalized serum calcium but the patient died on POD 105 due to multiple liver metastases. HHM associated with colon cancer is very rare. To our knowledge only 20 cases have been reported worldwide. Histopathologic studies revealed that there were seven cases of adenosquamous carcinoma, three cases of poorly differentiated carci-noma and three cases of adenocarcinoma which differentiation was not described. There was only one case of undifferentiated carcinoma, and this is the second case.