Denosumab is Effective for Controlling Serum Calcium Levels in Patients with Humoral Hypercalcemia of Malignancy Syndrome: A Case Report on Parathyroid Hormone-related Protein-producing Cholangiocarcinoma

Treatment of Hypercalcemia of Malignancy

The treatment of hypercalcemia of malignancy (HCM) consists of enhancing renal calcium excretion, mostly through hydration with isotonic fluids and the use of antiresorptive therapies. Intravenous zoledronic acid is currently the first-line treatment. Subcutaneous denosumab is used for bisphosphonate-refractory hypercalcemia and in patients with renal failure. There is no evidence that bisphosphonates prevent the occurrence of HCM. Conversely, denosumab, compared with zoledronic acid, is associated with a lower risk of HCM, both first episode and recurrence, in patients with breast cancer and multiple myeloma.

Hypercalcemia Associated with Extramammary Paget's Disease

Hypercalcemia of malignancy occurs in up to one third of patients at some point during the course of their advanced stage. The majority of them is caused by humoral hypercalcemia of malignancy due to systemic secretion of parathyroid hormone–related protein (PTHrP) by tumor cells. Extramammary Paget's disease is a slow-growing cutaneous malignancy commonly limited to the epidermis of the anogenital region, but rarely becomes invasive and metastatic to distant sites. Herein, we report a 70-year-old male patient with metastatic extramammary Paget's disease. He consulted our hospital with altered consciousness and tumor in his genital area. Physical examination revealed erythematous plaque with a tumor on the scrotum and perineum. It was diagnosed as extramammary Paget's disease (multiple liver metastases and multiple lymph node metastases by skin biopsy and image examination). Increases in serum-corrected calcium and PTHrP-intact levels (15.3 mg/dL and 66.1 pg/L, respectively) were confirmed. PTHrP immunohistochemistry showed positive staining in the tumor cells. We diagnosed humoral hypercalcemia of malignancy. We treated hypercalcemia with saline, furosemide, zoledronic acid, and elcatonin. Regarding the local control of the tumor, 30 Gy/10 Fr electron beam therapy was performed. However, treatment with zoledronic acid was only temporally effective to correct hypercalcemia, and an increased serum calcium level developed again. Concurrently, the liver metastases were rapidly enlarged, and his general condition gradually deteriorated. The patient died on day 55. When patients with extramammary Paget's disease show unconsciousness, serum calcium level should be measured and PTHrP-producing tumor distinguished.

Combined Hepatocholangiocarcinoma Associated with Humoral Hypercalcemia of Malignancy and Chronic Inflammatory Demyelinating Polyneuropathy

Paraneoplastic syndromes are often a diagnostic challenge to doctors and may have a heterogeneous presentation, including humoral hypercalcemia of malignancy (HHM), most commonly caused by squamous cell cancer and renal, ovarian, endometrial, and breast cancer. Chronic inflammatory demyelinating polyneuropathy (CIDP) has been described in patients affected by several types of cancer, especially hematologic malignancies, and a possible paraneoplastic pathogenesis of this neurological disease has been suggested. This report describes a 56-year-old man with a history of CIDP diagnosed 3 months earlier and persistently elevated aminotransferases for 18 months who was admitted to our internal medicine unit with abdominal pain, fatigue, and severe hypercalcemia with low serum intact parathyroid hormone. Parathyroid hormone-related protein (PTH-rP) was markedly high. Liver imaging showed a large hepatic mass in the right lobe, and percutaneous ultrasound-guided biopsy revealed histopathological findings consistent with a combined hepatocholangiocarcinoma (CHCC). We supposed that both HHM and CIDP could represent a paraneoplastic manifestation of CHCC.

Hypercalcemia of Malignancy in a Dog Diagnosed With Cholangiocellular Carcinoma

A 4-year-old, neutered male Golden Retriever was presented with a 1-week history of weight loss, polyuria, and polydipsia. The diagnostic workup showed an increased ionized calcium concentration, mild increase in serum creatinine and urea concentration, and severe hyperlipasemia. A complete abdominal ultrasound revealed multiple hepatic nodules. A cytological diagnosis of malignant epithelial neoplasia, highly suggestive of bile duct adenocarcinoma was made. In order to confirm the presumptive diagnosis of hypercalcemia of malignancy due to the presence of a hepatic neoplasia, serum parathormone-related peptide concentration was measured, and the result revealed an increased concentration. The dog was hospitalized and received supportive treatments consisting of intravenous furosemide and fluid therapy. After ruling out lymphoma and hypoadrenocorticism, oral prednisone was initiated and ionized calcium concentration decreased gradually down to normal concentration after 7 days of hospitalization. Chemotherapy with intravenous epirubicin was initiated based on the cytological diagnosis. One month after diagnosis and due to the worsening of its clinical condition, the dog was humanely euthanized. Postmortem examination confirmed a cholangiocellular carcinoma. To our knowledge, this is the first report of malignant hypercalcemia associated with cholangiocellular carcinoma in a dog.

Hypercalcemia of Malignancy

Hypercalcemia of malignancy (HCM) is a common concern in patients being treated for cancer, affecting over a quarter of this population. There are multiple causes of HCM, including humoral HCM, osteolytic HCM, ectopic hyperparathyroidism, and vitamin D-secreting lymphomas. Common signs and symptoms of HCM can range from mild gastrointestinal disturbances and fatigue to seizures, coma, or even cardiac arrest depending on the severity of the laboratory abnormality. Treatment has evolved in recent years and varies based on the underlying cause of the HCM. Management options include aggressive hydration, bisphosphonates, denosumab, calcitonin, and corticosteroids. It is imperative that advanced practitioners understand the pathophysiology behind the HCM so that proper treatment can be chosen. Early and appropriate treatment is key to successful outcomes. It is also important for continuous monitoring to occur alongside treatment for HCM to prevent potential adverse effects. Finally, the ultimate resolution of HCM comes only from the treatment of the underlying malignancy; therefore, all previously undiagnosed patients should be referred to an oncologist early after HCM is recognized.