Endocrine Abstracts

Introduction: Hypercalcemia is often observed in patients with cancer, secondary to the production s of parathyroid hormone (PTH)-related peptides. However, the association of primary hyperparathyroidism (pHPT) and colon cancer is rarely reported.

Case: We present the case of a 76 years old female patient, who was operated one year ago of for a low-grade colorectal adenocarcinoma. As part of her routine workup of her disease she underwent a phosphocalcic assessment which showed hypercalcemia at 120 mg/l, hypophosphatemia at 19 mg/l, an elevated PTH above 300 pmol/l and a 24-hour calciuria of 350 mg/day. The parathyroid Sestamibi scan was performed and the findings were suggestive of a left inferior parathyroid focus. The patient underwent a left inferior parathyroidectomy and the anatomopathological examination was in favor of a parathyroid adenoma.

Discussion and Conclusion: Calcium is considered as a potential anticarcinogenic, these findings can be explained by two possible mechanisms. Firstly, it neutralizes the promoter activity of fatty acids and bile acids in colorectal carcinogenesis. Secondly, calcium is believed to reduce crypt cell hyperproliferation so a decreased level of calcium can lead to hyperproliferation of the colorectal mucosa. In primary hyperparathyroidism the increase in PTH activates 1,25(OH)2D and promotes calcium absorption in the intestine. As a result, the level of calcium in the lumen is decreased, which leads to an elevated risk of colorectal cancer.