A Case of Pheochromocytoma Producing Parathyroid Hormone-Related Protein and Presenting with Hypercalcemia*

Abstract

A 54-yr-old man with a left adrenal pheochromocytoma showed mild hypercalcemia and elevated nephrogenous cAMP. Serum levels of PTH and 1,25-dihydroxyvitamin D3 were not elevated. Postoperatively, serum calcium and nephrogenous cAMP declined to normal ranges. Pathologically, the tumor was a benign pheochromocytoma. The clinical findings resembled those of humoral hypercalcemia of malignancy (HHM), and PTH-related protein (PTHrP) immunoreactivity was detected in the tumor extract at a concentration of 80.7 pmol/g wet wt, which is high compared to levels in malignant tumors causing HHM. Production of PTHrP was further confirmed by the demonstration of PTHrP mRNA with Northern blot hybridization analysis. Gel filtration of the extract revealed the presence of at least two different molecules with both immunological and biological activities. One of the peaks appeared close to PTHrP-(1-34), and the other between cytochrome-c and BSA. The latter showed a higher bioactivity to immunoreactivity ratio. These data indicate the multiplicity of PTHrP molecules in pheochromocytoma and support the idea that PTHrP produced by pheochromocytoma causes hypercalcemia in a similar fashion as HHM.

Hypercalcemia in pregnancy – a multifaceted challenge: case reports and literature review

“…The literature reports a few cases associated with the presence of dermoid cysts, pheochromocytomas, and fibromas 16, 19, 20, 21, 22, 23, 24, 25. We have identified six published cases of hypercalcemia secondary to benign uterine fibromas.…”

Thyroid Follicular Adenoma Producing Parathyroid Hormone-related Protein with a Normal Serum Calcium Level

“…PTHrP has also been reported to be the main factor associated with humoral hypercalcemia of malignancy (HHM) (4,5). There are several reports showing hypercalcemia associated with high plasma PTHrP levels in patients with benign tumors (6)(7)(8)(9)(10)(11)(12). However, this is the first report, to our knowledge, of a patient with a normal serum calcium level who had a benign tumor producing PTHrP.…”

Hypercalcemia during Pregnancy, Puerperium, and Lactation: Review and a Case Report of Hypercalcemic Crisis after Delivery Due to Excessive Production of PTH-related Protein (PTHrP) without Malignancy (Humoral Hypercalcemia of Pregnancy)

“…A female child weighing 1766 g was born by spontaneous delivery in good condition with an Apgar score of [8][9]. No abnormalities were noted on physical examination.…”

“…HHM may also develop in pregnant women with various PTHrP-producing tumors. PTHrP-producing tumors are, however, not always malignant and several patients with PTHrP-producing benign tumors have been reported (humoral hypercalcemia of benignancy) [9][10][11][12].…”