Asymptomatic Multiple Myeloma Presenting as a Nodular Hepatic Lesion: A Case Report and Review of the Literature

Abstract

Background: Plasma cell myeloma is the most common primary bone malignancy in adults. However, liver involvement in the form of an initial and asymptomatic nodular plasmacytoma is exceedingly rare.

Case report: A 64-year-old male was found to have a right hepatic lobe nodule on a routine abdominal ultrasound prior to bariatric surgery. Liver biopsy revealed a plasma cell neoplasm that, given the location of the lesion, was favored to represent a lymphoma with prominent plasmacytic differentiation. Positron emission tomography (PET) demonstrated a hypermetabolic hepatic mass and identified multiple destructive bony lesions. Biopsy of a clavicular lesion revealed sheets of plasma cells and confirmed the diagnosis of multiple myeloma. The patient underwent 6 cycles of chemotherapy with cyclophosphamide, bortezomib, and dexamethasone before transitioning to lenalidomide and dexamethasone because of early disease progression. Although the patient had International Staging System I (low-risk) disease, his disease demonstrated an aggressive clinical course and resistance to multiple lines of therapy.

Conclusion: Extramedullary nodular hepatic plasmacytoma is exceedingly rare. Nevertheless, extramedullary plasmacytomas should be included in the differential diagnosis of patients with indistinct hepatic lesions visualized on computed tomography scan, especially if PET scans show associated bony lesions. In general, extramedullary plasmacytomas are a poor prognostic sign and a harbinger of an aggressive clinical course in the context of multiple myeloma.

Keywords: Hypercalcemia; liver neoplasms; multiple myeloma; neoplasms–plasma cell; plasmacytoma.

Figure.

A: The lesion is barely visible on contrast-enhanced computed tomography scan (arrow). B: Core sections of an ultrasound-guided liver biopsy show confluent expansile sheets of plasma cells (hematoxylin and eosin [H&E] stain, ×20). C: Touch imprints of the liver biopsy reveal discohesive plasmacytoid cells and naked nuclei (Diff-Quik stain, ×100). D: Chromogenic in situ hybridization analysis demonstrates cytoplasmic kappa light chain restriction (immunohistochemical stain, ×40). E: Metabolically active lesions in the right hepatic lobe can be seen on positron emission tomography. F: Metabolically active lesions in the right clavicle can be seen on positron emission tomography. G: Core sections of right clavicular bone marrow biopsy show sheets of plasma cells (H&E stain, ×40).