Hypercalcemia induced by parathyroid hormone-related peptide after treatment of squamous cell carcinoma of oral cavity.

Squamous cell carcinoma of the head and neck is a rare cause of humoral hypercalcemia of malignancy. This paraneoplastic syndrome is usually one of the presenting symptoms of the disease. We report a case of squamous cell carcinoma of the oral cavity that presumably elaborated parathyroid hormone-related peptide (PTH-rP) and caused hypercalcemia only after radiotherapy and chemotherapy.