Teaching point: In the context of malignancy with lytic bone lesions, strongly hypoechoic liver nodules should alert for the possible diagnosis of extramedullary multiple myeloma.
An 81-year-old man was found to have multiple bone lesions on a thoracic computed tomography (CT) in the context of pneumonia. The patient only reported a mild weight loss and ordinary low back pain. His physical examination was unremarkable. Routine laboratory tests results were normal.
Abdominal contrast-enhanced computed tomography (CECT) showed disseminated osteolytic bone lesions and two barely visible hypoattenuating liver nodules (arrows, Figure 1).
Ultrasound (US) of the hepato-biliary tract confirmed two homogeneous strongly hypoechoic liver nodules, measuring 20 and 12 mm in diameter. The lesions’ margins were well-defined, with neither hypoechoic halo sign, nor posterior acoustic enhancement or shadowing (arrow, Figure 2).
Since no primary tumor was identified, percutaneous US-guided fine-needle biopsy of one of the liver lesions was performed, which revealed unexpectedly extramedullary location of multiple myeloma (MM). The immunochemistry staining of kappa light chain was positive (Figure 3).
To illustrate the imaging characteristics of the bone lesions, a magnetic resonance imaging (MRI) was realized and confirmed malignant marrow-replacing lesions, especially on the spine (arrows, Figure 4).
Multiple myeloma (MM) is the most common primary bone malignancy among adults. Soft tissue involvement of MM is uncommon upon diagnosis and is referred to as extramedullary myeloma (EM) . There are two histological patterns of hepatic myeloma:
The approach to a patient with strongly hypoechoic liver nodules remains challenging. The differential diagnosis is broad and includes: benign focal liver lesions, hepatocellular or cholangiocellular carcinomas, metastatic carcinomas, metastatic endocrine tumors, and lymphoma. Although uncommon, EM should be included in the differential diagnosis, especially in the context of associated lytic bone lesions.
The authors wish to thank Dr Emmanuelle Laterre for the histopathology image.
The authors have no competing interests to declare.
Bladé, J, Fernandez de Larrea, C, Rosinol, L, et al. Soft-tissue plasmacytomas in multiple myeloma: Incidence, mechanisms of extramedullary spread, and treatment approach. J Clin Oncol. 2011; 29(28): 3805–3812. DOI: https://doi.org/10.1200/JCO.2011.34.9290