title: PTHrP-mediated hypercalcemia in a calcitonin-producing islet cell tumor.
abstract: Calcitonin is a peptide hormone that may decrease serum calcium levels. This case report describes a patient with a calcitonin-producing islet cell tumor who was also hypercalcemic. Parathyroid hormone-related peptide (PTHrP) levels were elevated. No other cause for hypercalcemia was found. The hypercalcemia resolved when the tumor was treated with chemotherapy. PTHrP levels also decreased with the chemotherapeutic treatment. This is the first report of a patient with a calcitonin-producing islet cell tumor and hypercalcemia mediated by PTHrP.
authors.affiliation: Section of Endocrinology and Metabolism, Lahey Clinic, Burlington, MA 01805, USA.
authors.forename: T B
authors.initials: TB
authors.lastname: Kaye