Case Presentation: A 61-year-old male presented to the emergency department (ED) with back pain. Approximately 1.5 months prior to presentation, he developed a sudden onset left clavicle pain. His pain progressed to involve multiple areas of the body, until finally he started to experience a severe low back pain, prompting evaluation.In the ED, examination was significant for tenderness of multiple bony areas. Bilateral lower extremity strength exam was limited due to severe back pain. Complete blood count and basic metabolic panel were normal. CT images revealed widespread osseous lytic lesions. MR lumbar spine showed a pathologic T12 fracture with epidural soft tissue component resulting in advanced spinal canal stenosis with cord compression. He was found to have a new urinary retention. High-dose steroids were initiated, but he did not undergo emergent decompression as examination was not consistent with myelopathy. He was admitted for expedited work-up and pain control.Work up revealed immunoglobulins within normal limits; however, kappa free light chain (FLC) was elevated at 153 mg/dL (0.3300-1.94 mg/dL), with kappa to lambda FLC ratio 140. Prostate-specific antigen was within normal limits. Bone marrow biopsy was performed, with 5-9% kappa light chain-restricted plasma cells. Bone biopsy of sternal lytic lesion was performed, revealing kappa light chain-restricted plasma cell neoplasm. With high dose steroids and palliative radiation therapy to the T12 lytic lesion, patient’s pain and functional status improved, and urinary retention resolved. He was discharged with plans for outpatient chemotherapy for diagnosis of kappa light chain multiple myeloma (MM).

Discussion: This is a case of a patient with a new diagnosis of kappa light chain MM. Not infrequently, MMs are first diagnosed with a hospitalization due to intolerable pain from lytic bone lesions. Thus, it is crucial for hospitalists to be able to initiate work-up of and recognize MM. This case highlights the importance of obtaining serum FLC along with serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP) for diagnosis of MM.This case is particularly notable, as the patient did not present with the classic features of MM (hypercalcemia, anemia, or renal dysfunction) except for osseous lytic lesions. However, patient had myeloma-defining biomarkers, with FLC ratio of greater than 100. Thus, patient met diagnostic criteria for kappa light chain MM, which comprises 15-20% of newly diagnosed MM cases. Adding to the complexity to this case was management of patient’s spinal cord compression from the pathologic fracture. In cases of suspected hematologic malignancy-related spinal cord compression, prompt initiation of high-dose steroids and interdisciplinary discussion with Hematology, Neurosurgery, and Radiation Oncology are imperative to manage the cord compression and the underlying malignancy. In addition to decompression, radiation therapy has the added benefit of pain control; thus, providers should have a low threshold to involve Radiation Oncology.

Conclusions: Patients with MM can present without the classic clinical features of MM. Hospitalists are advised to recognize MM and initiate work-up including SPEP, UPEP, and serum FLC even in the absence of some of the features of end-organ damage if suspected clinically. Pain control, decline in functional status, and spinal cord compression are only a few of the complications that can be seen in a new diagnosis of MM, as is seen in this patient.