Humoral hypercalcemia complicating adenosquamous carcinoma of the proximal colon.

Hypercalcemia as a complication of carcinoma of the colon is uncommon (1). It usually occurs in the presence of anorectal or rectal carcinoma that metastasizes to the lumbosacral vertebrae (2-4). Hypercalcemia complicating colon carcinoma in the absence of bone metastases--so-called humoral hypercalcemia of malignancy or paraneoplastic hypercalcemia--is rare. Only two such cases associated with adenocarcinoma of the colon (5,6) and two cases associated with adenosquamous carcinoma of the distal colon (rectum and sigmoid) (7) have been reported. We describe the first reported case of an adenosquamous carcinoma of the cecum and ascending colon that was accompanied by severe humoral hypercalcemia. The hypercalcemia was associated with a parathyroid hormone (PTH)-like substance.