Endocrine Abstracts

Introduction: Mild hypercalcaemia can present in 10–15% of hyperthyroid patients. In contrast, its incidence in B cell lymphoma is considerably less (7–8%) but its levels are much higher. We report a patient with hypercalcemia secondary to both thyrotoxicosis and lymphoma.

Case report: A 55 year-old lady presented with non specific symptoms of appetite loss and lower limb weakness. Comorbidities included hypertension, diabetes mellitus, hyperlipidaemia and a previous history of consumption of traditional herbal supplements. Examination was unremarkable except for bilateral hand tremors. There was no hepatosplenomegaly or lymphadenopathy. Laboratory results: Ca(adj) 3.59 mmol/l (RI: 2.15–2.58), PO4 1.2 mmol/l (RI: 0.8–1.6), PTH<0.6 pmol/l, 25(OH)VitD 19 ug/l (RI: 30–50). fT₄ 67 pmol/l (RI: 8–21), TSH 0.03 mIU/l (RI: 0.34–5.6). TRAb 7.5 IU/l. A normal short synacthen test excluded concomitant hypocortisolism. A presumptive diagnosis of PTH-independent hypercalcaemia due to thyrotoxicosis was made. A dose of pamidronate normalised the calcium levels but despite treatment with anti-thyroid medications, hypercalcemia rapidly recurred. A search for malignancy revealed elevated LDH and beta2 microglobulin and multiple lymphadenopathy on abdominal imaging. This was followed up with a bone marrow examination showing B cell lymphoma. She was subsequently referred to hematology for chemotherapy.

Conclusion: Despite the presence of a known cause of hypercalcemia, malignancy must always be extensively investigated for and excluded when calcium levels are markedly elevated. Hypercalcemia in B-cell lymphoma is not uncommon and carries a poorer prognosis, thus it is crucial that diagnosis be suspected and made early so that appropriate treatment can be carried out.