Severe hypercalcemia in a patient with chronic lymphocytic leukemia and non-small cell lung carcinoma

Rationale: Hypercalcemia is a common finding in patients with advanced-stage cancers. Paraneoplastic hypercalcemia is commonly associated with dismal prognoses, with survival rates of about 3 months. In this paper, we report on a patient with advanced chronic lymphocytic leukemia and non-small cell lung carcinoma who developed severe hypercalcemia and discuss the diagnosis and treatment of this metabolic complication. Patient concerns: A 56-year old male with a 2-year history of Rai stage IV chronic lymphocytic leukemia presented with life-threatening hypercalcemia. Positron emission tomography/computed tomography revealed a suspicious lung lesion. A transbronchial biopsy was performed from the upper left lobe. Due to the small size of the specimen, immunohistochemical markers were performed and revealed positive staining for cytokeratin 7 and negative for TTF-1, napsin A and p 40, which were consistent with non-small cell lung carcinoma. Diagnosis: Humoral hypercalcemia of malignancy was diagnosed. Intervention: The patient was treated with saline infusion, calcitonin, intravenous pamidronate, followed with denosumab. Outcomes: The hypercalcemia was successfully treated and the patient's calcium levels returned to normal. Further evaluation revealed a non-small cell lung carcinoma as a second primary malignancy. The patient was treated with venetoclax for his refractory CLL and received chemotherapy and immunotherapy for lung adenocarcinoma. Several days after starting venetoclax, he developed Legionella pneumonia and short time after the second course of chemotherapy, a severe sepsis occurred and he passed away. Lessons: Coexistence of 2 unrelated malignancies, whichever could be a reason for hypercalcemia of malignancy is a rare event. Severe hypercalcemia, which is possible but rare feature of CLL should be a reason for further prompt evaluation.