Primary Ovarian Lymphoma Manifesting with Severe Hypercalcemia

Persistent and moderate hypercalcemia related to an ovarian clear cell adenocarcinoma: Pre- and postoperative parathyroid hormone related-peptide and 1,25-dihydroxyvitamin D3 levels

OBJECTIVE

To evaluate the role of PTH-related peptide (PTH-rP) and 1,25-dihyhydroxyvitamin D3 in a case of hypercalcemia related to an ovarian adenocarcinoma.

DESIGN

We report a case of humoral hypercalcemia in a patient aged 74 yr with a clear cell adenocarcinoma of the right ovary at an early stage of its development (stage T1aN0M0) revealed by moderate and persistent hypercalcemia (variable level between 2.7 and 3.2 mmol/l without any treatment) over six months.

METHODS

PTH-rP and 1,25-dihydroxyvitamin D3 were measured in blood samples taken before and after hysterectomy and bilateral salpingooophorectomy and in blood samples taken intraoperatively from the right ovarian vein and a peripheral vein.

RESULTS

High levels of plasma PTH-rP and 1,25-dihydroxyvitamin D3 concomitant with high serum calcium and low PTH levels were found before surgery, which was followed by normalisation of all parameters studied. A concentration gradient was found regarding plasma PTHrP (right ovarian vein 60.4 pmol/l, peripheral vein 4.5 pmol/l), not 1,25-dihydroxyvitamin D3.

CONCLUSION

1) moderate and persistent hypercalcemia can be observed at an early stage of an ovarian carcinoma; 2) the gradient of PTH-rP concentration between the samples taken from the right ovarian vein and a peripheral vein provides evidence for a direct secretion of PTH-rP by the ovarian tumor; 3) the increased 1,25-dihydroxyvitamin D3 level is not related to a direct ovarian production, but is a consequence of PTH-rP secretion.

[Hypercalcemia of malignancy: clinical features, diagnosis and treatment]

Hypercalcemia associated with malignancies is reported in up to 20 to 30% of patients with cancer during the course of the disease, and points to a poor prognosis. Symptoms related to the central nervous system, as progressive mental impairment, stupor and coma, predominate. Alterations in kidney function (water-concentrating defect leading to polyuria) and gastrointestinal tract (anorexia, nausea, vomiting) corroborate to dehydration and a further increase in serum calcium. Cancer-induced hypercalcemia may be classified as: 1) local osteolytic hypercalcemia (LOH), due to marked increase in osteoclastic bone resorption in areas surrounding the malignant cells within the marrow space; 2) humoral hypercalcemia of malignancy, caused by the secretion of parathyroid hormone-related protein (PTHrP) by the malignant tumor; 3) ectopic hyperparathyroidism; 4) 1,25(OH)2 D-secreting tumors. Adequate control of hypercalcemia is necessary to give the patient time to respond to anti-cancer therapy. Volume expansion with saline will correct dehydration, improve glomerular filtration and increase urinary calcium excretion, which may be further stimulated by loop diuretics. Intravenous bisphosphonates are the most effective agents to control hypercalcemia, as they block osteoclastic osteolysis and also have antitumoral effects, decreasing bone metastases. New approaches to control the skeletal manifestations of malignancies are anti-PTHrP and anti-RANKL antibodies, osteoprotegerin, and also proteasome inhibitors in the case of multiple myeloma.