What complication might occur in patients with untreated renal cell carcinoma?

In patients with untreated renal cell carcinoma, hypercalcemia can occur due to the paraneoplastic syndromes associated with the disease. This is often a result of the secretion of parathyroid hormone-related peptide (PTHrP) by the tumor cells, which mimics the action of parathyroid hormone and increases calcium release from bones, enhances intestinal absorption of calcium, and decreases renal excretion of calcium.

The presence of hypercalcemia can lead to a variety of symptoms, including increased thirst, frequent urination, fatigue, nausea, and confusion. Identifying and managing hypercalcemia is critical in the care of patients with renal cell carcinoma to alleviate these symptoms and prevent further complications.

Other choices relate to different conditions or mechanisms that are not typically associated with untreated renal cell carcinoma directly.