Category: Calcium/Bone Disorders

Monitor: 14

14 - PTHRP-INDUCED HYPERCALCEMIA IN A PATIENT WITH MULTIPLE MYELOMA

Saturday, Apr 27
11:00 AM – 11:30 AM

Objective :

Hypercalcemia is the most common metabolic abnormality in multiple myeloma (MM).  It is primarily the result of direct bone invasion by tumor: local osteolytic hypercalcemia (LOH) and several cytokines have been implicated. PTH-related peptide (PTHrP)—causing humoral hypercalcemia of malignancy (HHM)— is the most common cause of hypercalcemia in solid tumors and squamous cell tumors and is a less known cause of hypercalcemia in patients with MM. We herein present a case of MM with plasmacytoma and PTHrP-induced hypercalcemia. 


Methods : N/A


Results : N/A


Discussion : An 80 year-old lady presented with incidentally noted hypercalcemia and acute kidney injury. She had been experiencing constipation and fatigue for several weeks. Exam revealed normal vital signs, normal heart tones, and clear lungs. Patient was appropriately oriented with good muscle strength and no focal neurologic deficits. Labs showed hypercalcemia with albumin-corrected Ca at 13.8 mg/dL, normal phosphorus at 4.1 mg/dL, AKI (BUN, 43 mg/dL; Cr, 3.14 mg/dL), elevated urine protein/creatinine ratio (1.7 mg/g) and normocytic anemia (Hb 9.3 g/dL). Peripheral blood smear revealed Rouleaux formation. Iron studies were consistent with anemia of chronic disease. Folate was normal (6.1 ng/mL) and vitamin B12 was low (200 pg/mL). Intact PTH was low-normal at 14 pg/mL. 25 hydroxy-vitamin D was normal at 50.9 ng/mL. 1,25 dihydroxy-vitamin D was low at 5.4 pg/mL. PTHrP was elevated at 8.9 pmol/L (normal 0.0-3.4). SPEP revealed a 0.87 g/dL M protein. Serum free light chain analysis showed a low kappa/lambda ratio of 0.16, and serum immunofixation revealed an IgA lambda monoclonal protein (938 mg/dL).  Bone survey revealed multiple lytic lesions of the axial and appendicular skeleton. CT-head showed a large lytic left parietal mass destroying the left parietal bone. The patient subsequently developed right-sided weakness and expressive aphasia. A repeat CT-head demonstrated the above lesion with severe mass effect on the brain with cerebral edema. Patient underwent craniectomy with resection of the large left parietal brain tumor; pathologic analysis revealed diffuse involvement by sheets of plasma cells, positive for CD138, consistent with plasmacytoma. A bone marrow biopsy revealed 30% plasma cells. 


Conclusion :

We presented a case of MM with plasmacytoma, PTHrP-induced hypercalcemia, and osteolytic bone lesions. This case emphasizes that hypercalcemia in MM is not only the result of LOH and cytokines but PTHrP has an important role in its pathogenesis. It also stresses the fact that plasma cells do secrete PTHrP. Despite the fact that PTHrP is well known to cause HHM in a variety of cancers, its role in MM seems often overlooked. 

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Deepthi Busayavalasa

Internal Medicine Resident Physician
University of Illinois at Chicago/Advocate Christ Medical Center

Deepthi Busayavalasa is a third-year internal medicine resident at UIC/Advocate Christ Medical Center. She will be pursuing a hematology and medical oncology fellowship at St. Louis University in the Fall of 2019.

Matthew J. Mandell

Internal Medicine Resident Physician
University of Illinois at Chicago/Advocate Christ Medical Center
Chicago, Illinois

Matthew Mandell is a second-year internal medicine resident at UIC/Advocate Christ Medical Center.

Joumana T. Chaiban

Associate Professor of Clinical Medicine; Internal Medicine Residency Program Research Director
University of Illinois at Chicago; Advocate Christ Medical Center, Department of Internal Medicine, Endocrinology Division

Dr. Chaiban is an attending endocrinologist at UIC/Advocate Christ Medical Center. She teaches UIC/ACMC internal medicine residents as well as UIC endocrinology & metabolism fellows from UIC. She also serves as the research director for the internal medicine residency at UIC/ACMC.

Deepthi Busayavalasa

Internal Medicine Resident Physician
University of Illinois at Chicago/Advocate Christ Medical Center

Deepthi Busayavalasa is a third-year internal medicine resident at UIC/Advocate Christ Medical Center. She will be pursuing a hematology and medical oncology fellowship at St. Louis University in the Fall of 2019.