# Relapsed Chronic Lymphocytic Leukemia Heralded by Parathyroid Hormone Related Peptide‐Mediated Hypercalcemia

## TL;DR

A patient with relapsed chronic lymphocytic leukemia presented with severe hypercalcemia caused by elevated parathyroid hormone-related peptide.

## Contribution

This case highlights parathyroid hormone-related peptide-mediated hypercalcemia as a rare sign of CLL/SLL relapse.

## Key findings

- Hypercalcemia was linked to elevated parathyroid hormone-related peptide in the context of CLL/SLL recurrence.
- The patient initially responded to treatment but later developed refractory disease.
- No evidence of Richter transformation was found in the biopsies.

## Abstract

Hypercalcemia is a common, serious complication in patients with malignancy and is associated with significant morbidity. Compared to patients with solid tumor malignancies, the reported incidence of hypercalcemia in patients with indolent lymphoid malignancies is lower and rare in those with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). In this report, we describe the case of a patient with a history of CLL/SLL previously treated with multiple lines of therapy and thought to be in remission who presented with symptomatic, severe hypercalcemia. Her calcium initially improved; however, it increased after discontinuation of steroids despite aggressive fluid resuscitation, calcitonin, and bisphosphonate therapy. Following an extensive laboratory and radiographic evaluation, her hypercalcemia was concluded to be secondary to elevation in serum parathyroid hormone‐related peptide in the setting of recurrent CLL/SLL. Notably, the patient had no evidence of Richter transformation and initially responded well to steroids, denosumab, and CLL‐directed therapy; however, she later had refractory CLL/SLL and hypercalcemia. Hematologic malignancy, including CLL/SLL, could be considered in the differential diagnosis of hypercalcemia and can be present either at the time of initial diagnosis or signal disease relapse in the appropriate context.

Recurrent chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) presenting with severe parathyroid hormone related peptide‐mediated hypercalcemia. Bone marrow and paravertebral biopsies confirmed relapse without evidence of Richter's transformation.