Hypercalcemia associated with squamous cell carcinoma of tongue

To present a case and to review the relationship between tumor production of parathyroid hormone-related protein (PTHrP) and hypercalcemia in oral squamous cell carcinoma (SCC), with emphasis on tongue cancer.

We describe a patient with advanced, locally invasive SCC of the tongue in whom hypercalcemia developed as a result of PTHrP production by the tumor. In addition, the medical literature regarding PTHrP and hypercalcemia associated with malignant disease is reviewed.

A 65-year-old man, who was admitted to the hospital because of one episode of unresponsiveness, was found to have a large, necrotic, ulcerated lesion overlying the left mandibular area. After biopsy of the tumor and total body imaging, he was diagnosed with advanced, locally invasive, poorly differentiated SCC of the tongue, stage T4 N1 M0. On admission, the serum calcium concentration was 12.5 mg/dL (normal range, 8.5 to 10.7), and the serum albumin level was 2.2 g/dL (normal range, 3.5 to 5.5). The serum intact parathyroid hormone level was 26 pg/mL (normal range, 10 to 65); the PTHrP level was 13.1 pmol/L (normal, <1.3). Hypercalcemia attributable to production of PTHrP by the tongue SCC was diagnosed. Initial treatment of the hypercalcemia with vigorous hydration yielded a limited response. Intravenous administration of pamidronate initially decreased the serum calcium level to 5.2 mg/dL, but then it progressively increased to 8.6 mg/dL during the next 4 weeks. The patient refused further treatment and died after 1 month.

To our knowledge, this is the first case of hypercalcemia associated with SCC of the tongue in which the serum PTHrP level was measured and reported to be high. It should be measured in other similar cases.