Cases of Extra- Medullary Myeloma Presenting As Liver Infiltrates: A Single Community Hospital Experience

Introduction:

Multiple Myeloma (MM) accounts for 13% of all hematologic malignancies. Plasma cells (PC) proliferation is mainly restricted to the bone marrow (BM) in most of the patients. Extramedullary myeloma (EMM) is defined by the PCs outside the bone marrow. The prevalence of EMM in myeloma patients has been reported at 7 to 15 percent in newly diagnosed patients and from 6 to 20 percent in relapsed setting. Patients with EMM have poor prognosis with a median overall survival of < 6 months. This abstract presents two cases of MM with initial presentation as a liver infiltrate.

Cases:

Case one: 74-year-old female presented with epigastric pain. Physical exam was unremarkable. Labs showed Hemoglobin (Hb) 8.3 g/dL, Creatinine (Cr) 2.0 mg/Dl and normal liver function test. Ultrasound showed multiple hypoechoic liver nodules. Biopsy of the liver nodule confirmed plasma cells. Her kappa/lambda ratio 3338, Lactate dehydrogenase (LDH) 423 IU/L, beta2 microglobulin was 9 mg/L. Serum and urine immunofixation(IFE) both confirmed a monoclonal kappa light chain clone. Skeletal survey was negative. BM biopsy showed 30 % kappa clonal plasma cells. Fluorescence in situ hybridization was positive for hyperdiploidy of chromosomes 7, 9, 11, 14, and 17 with partial deletion of IgH gene. Treatment with CyBorD (weekly dexamethasone 20 mg, bortezomib 1.3 mg/m², and cyclophosphamide 300mg/m2) was started. After 6 months therapy, patient achieved partial response. Then her regimen was switched from CyBorD to VRD (Revlimid 10 mg, bortezomib 1.3 mg/m² and dexamethasone 40 mg) because of severe side effect. She achieved a good partial response.

Case two: 57-year-old male presented with right upper quadrant abdominal pain. Physical exam showed diffuse tenderness but no rigidity or guarding. Initial labs showed Hb 8.4g/dL, Cr 1. 7 mg/dL, total bilirubin of 3 mg/ dl, alanine aminotransferase 81 U/ l and aspartate aminotransferase 98 U/ l. CT abdomen pelvis showed metastatic disease to omental implants, splenomegaly and an enlarged liver. Patient underwent surgery in which it was noticed that omentum was adhered to stomach wall whose wedge resection showed plasma cells infiltrate. Liver biopsy also showed diffuse myeloma infiltration. His kappa /lambda ratio 0.0029, LDH 2187 IU/ L, beta 2 microglobulin was 8 mg/L. Serum electrophoresis showed M spike 3. 8 g with IFE confirmed IgG lambda band. Skeletal survey showed several osteolytic lesions in iliac bone. BM biopsy showed hypercellularity with 90 % plasma cells. Patient was started on CyBorD regimen. Repeat labs after first cycle was significant for rising free lambda light chain making us refer the patient to a University Hospital for further treatments. He was recently started on VDT- PACE ( bortezomib, dexamethasone, thalidomide, cisplatin, doxorubicin, cyclophosphamide, and etoposide).

Conclusion:

EMM with liver metastasis as initial presentation is rare. Since the low incidence of EMM there are no specific treatment guidelines. There are no clear prognostication factors for EMM. Patients are treated in same way as MM. The current initial treatment relies on whether the patient is a transplant candidate or not.

Our first patient showed a good response to treatment. However the second patient had primary refractory disease. Given his young age more intensive chemotherapy like VDT-PACE is a good choice If necessary, should be followed by a autologous transplantation or even allogenic transplantation and/ or involving CAR T- cell therapy.

A better understanding of how myeloma cells grow and thrive, as well as the biology of extramedullary tumors, is needed in order to develop better strategies for the treatment of EMM in future.