Introduction:
Hypercalcemia is commonly seen in the hospital setting, with multiple etiologies including hyperparathyroidism, malignancy, and drug side effects. In order to effectively determine the reversibility and treatment of hypercalcemia, the appropriate cause must first be ascertained with laboratory tests and imaging.

Case Report:
A 71-year-old female with bipolar disorder, hepatitis C, and hypertension presented with altered mental status (AMS) and hypercalcemia. The patient was noted to be on lithium and hydrochlorothiazide (HCTZ). Calcium was elevated to 14.8 mg/dL with normal renal function. Extensive workup revealed normal parathyroid hormone (PTH), low vitamin D, normal lithium levels, and elevated PTH-related peptide. Lithium and HCTZ were held and initially thought to be the cause. Despite aggressive fluids and bisphosphonate therapy the patient’s calcium levels remained high. Her AMS did not improve, therefore calcitonin therapy was initiated. After seven days of therapy, her calcium levels normalized. In the setting of hypercalcemia and mild anemia, Oncology was consulted for evaluation of multiple myeloma (MM). Serum protein electrophoresis (SPEP) showed a 4.22 g/dL spike with a broad band in the gamma region. Her serum kappa/lambda ratio was elevated to 2.01. Skeletal survey was negative for bony involvement, making MM less likely.

Final/Working Diagnosis:
In the setting of hepatitis C a right upper quadrant ultrasound showed evidence of cirrhosis with a hepatic mass. Alpha fetoprotein (AFP) was markedly elevated at 94500 ng/mL. Abdominal MRI confirmed a 12 cm space- occupying heterogeneous mass with early arterial enhancement and early venous washout. The patient was diagnosed with hepatocellular carcinoma (HCC), likely causing her hypercalcemia.

Management/Outcome/Follow-Up:
This patient was ruled out for excess vitamin D, hyperparathyroidism, drug side effects, and MM. Despite having hypergammaglobulinemia on SPEP the patient had a broad band, concerning for polyclonal gammopathy, a nonspecific finding in any inflammatory or reactive process. Polyclonal gammopathy is rarely seen in MM but for MM to cause hypercalcemia there must be bony involvement, not seen here. It is most likely that the hypercalcemia was caused by HCC as the markedly elevated AFP, MRI findings, and polyclonal gammopathy was diagnostic for HCC. Patient and family elected to pursue hospice care.