Primary hyperparathyroidism with breast carcinoma

Although hypercalcemia is a common complication of breast carcinoma (BC), it may be due to primary hyperparathyroidism (pHPT), which has a similar sex or age predilection to that of BC. The rate of underlying asymptomatic pHPT in BC patients with hypercalcemia is exceptionally high, so the clinical data were retrospectively analyzed.

To investigate coexistent pHPT in BC patients, the medical records of persons who had undergone surgery for primary BC without bone metastases between October 2004 and March 2008 at the Tsuchiura Kyodo General Hospital were retrospectively reviewed. The corrected serum calcium level was measured in all 243 patients. Ten patients who noted hypercalcemia above 11.0 mg/dl via the corrected serum calcium were selected in order to investigate pHPT.

Among the 243 patients investigated, 7 were diagnosed with pHPT, and 5 of those patients required surgical treatment. In all five patients, the parathyroids were pathologically diagnosed to have adenoma.

Primary hyperparathyroidism was diagnosed in 2.88% of the BC patients, which was more than expected, in comparison to the incidence of pHPT in adult women, which is 0.04-0.08%. It is important to assess whether pHPT is associated with the treatment of BC.