Nodular plasma cell myeloma of liver

Clinical History

A 56 year old female of short stature was admitted in our hospital with dull pain in the abdomen, severe lower back pain, decreased appetite and weight loss.
On physical examination, hepatomegaly with deep tenderness in right hypochondrium, tenderness in processus spinalis L3 to S1 was diagnosed. No splenomegaly/lymphadenopathy was noted. Erythrocyte sedimentation rate levels were raised (93mm/hr)

Imaging Findings

Trans-abdominal ultrasound revealed multiple hypoechoic nodular lesions in the liver [Fig 1]. Spleen and bilateral kidneys were not affected. Metastasis was taken into consideration and CECT of the abdomen was performed to identify the origin, using ionic contrast (iohexol) at a rate of 3 ml per second over 39 seconds using infusion pump . It revealed multiple non enhancing hypodense lesions in the right and left lobe of the liver in the arterial phase, becoming isodense and mildly hypodense at the equilibrium phase [Fig 2]. The CT bone window scan also revealed multiple lytic lesions in the vertebral bodies at different levels and the pelvic bones [Fig 3]. No other abnormalities were seen. A fine-needle liver biopsy under US guidance was performed, which revealed focal lesions of plasma-cell myeloma which were positive for immune-histochemistry staining of kappa light chain. Histopathologic examination of the left iliac crest confirmed the diagnosis of multiple myeloma[Fig 4].

Discussion

Multiple myeloma, also known as plasma cell myeloma, myelomatosis, or Kahler's disease (after Otto Kahler), is a cancer of plasma cells, a type of white blood cell normally responsible for producing antibodies. Myeloma cells proliferate in bone marrow and circulate through the bloodstream. Like benign plasma cells, they circulate through lymphatics and the reticulo-endothelial system. Hence spleen, liver or lymph node infiltrations are common. Liver lesions involving MM should be differentially diagnosed from other diseases; we describe a case of multiple nodular lesions in the liver unexpectedly proven to be multiple myeloma [1]. Multiple myeloma develops in 6.1 per 100, 000 people per year.
It is more common in men. Aetiology is not definitive; relation to radiation, benzene, organic solvents, herbicides, and insecticides, chronic inflammatory diseases, Kaposi’s sarcoma (HHV 8) has been proposed. Clinically presents with bone pain (60%)- back or chest, reduction in height, weakness and fatigue (32%), weight loss (24%), pallor, thoracic/lumbar radiculopathy and infections [2]. Multiple myeloma is diagnosed using blood tests (serum protein electrophoresis, serum free kappa/lambda light chain assay), bone marrow examinations, urine protein electrophoresis, and X-rays of commonly involved bones (vertebra plana, pepper pot skull etc).
Clinicians and radiologists have to keep in mind the extra-osseous occurrence of multiple myeloma (as their presence has been associated with a more aggressive disease) so that extensive unnecessary interventions can be avoided as the lesion mimicking a malignancy may be solitary plasmacytoma. In a case of multiple myeloma, the development of focal soft-tissue masses should be considered highly suspicious for extra-osseous myeloma even after stem cell transplantation. Transient enhancement in the arterial phase is an imaging finding in keeping with the hypervascular nature of active lesions of multiple myeloma. In the setting of non-secretory type multiple myeloma, where the disease may become elusive on serum laboratory tests, CT appearances of the liver lesions may be used as a surrogate marker for monitoring treatment response.
Multiple myeloma is considered to be incurable but treatable. Remissions may be induced with steroids, chemotherapy, proteasome inhibitors, immunomodulatory drugs such as thalidomide or lenalidomide, and stem cell transplants. Radiation therapy is sometimes used to reduce pain from bone lesions [3].
Take home message: CECT appearance of liver lesions can be a significant marker for extra-osseous multiple myeloma.

Differential Diagnosis List

Final Diagnosis

Nodular liver involvement in Grade II Multiple myeloma,

URL:	https://www.eurorad.org/case/12222
DOI:	10.1594/EURORAD/CASE.12222
ISSN:	1563-4086