July 2022, Volume 72, Issue 7

IMAGING CORNER

Extraosseous soft tissue uptake—in Multiple Myeloma

Kahkashan Bashir Mir  ( Department of Nuclear Medicine, NORI Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad )
Shazia Fatima  ( Department of Nuclear Medicine, NORI Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad )
Sadaf Batool  ( Department of Nuclear Medicine, NORI Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad )
Noreen Marwat  ( Department of Nuclear Medicine, NORI Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad )
Mohammad Faheem  ( Department of Nuclear Medicine, NORI Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad )
Ayesha Ammar  ( Department of Nuclear Medicine, NORI Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad )

Abstract

Tc-99m Methylene Diphosphonate (MDP) bone scintigraphy has been used for the assessment of benign as well as malignant skeletal conditions. Non-osseous radiotracer uptake on bone scan is an unusual finding. It is usually performed for metastatic bone disease, and is generally not an indication in multiple myeloma, as osteolytic lesions typically show no radiotracer uptake. Despite this, substantial number of multiple myeloma patients undergo bone scintigraphy due to their presentation imitating a metastatic bone disease. We describe a case of multiple myeloma, where extra osseous uptake in lung and diffuse hepatic, has been noted on bone scan.

 

Keywords: Bone scan, Multiple Myeloma, Extra osseous uptake, Amyloidosis

 

DOI: https://doi.org/10.47391/JPMA.22-82

 

Discussion

 

A 78-year-old male, with generalized body aches and acute kidney injury superimposed on chronic renal disease and deranged renal function tests underwent bone scan for the evaluation of possible metastatic bone disease with 20 mCi (740 MBq) of Tc-99m MDP administered IV. Whole-body imaging was done in anterior and posterior projections after four hours showing heterogeneous radiotracer uptake in bilateral ribs and in multiple thoracic and lumbar vertebrae, more prominent in T8-T12, L2-L5 with reduced vertebral height, indicating collapsed vertebrae. Diffuse radiotracer uptake was noted in right upper chest, most likely in right upper lobe along with hepatic uptake (Figure). Bone marrow aspiration showed plasmacytosis and eosinophilia. Serum protein electrophoresis revealed a band in fast gamma region, and on urine electrophoresis, faint band was seen in gamma region. Trephine bone marrow biopsy showed active myelopoiesis showing all stages of myeloid series with increased eosinophilia and plasma cells, establishing the diagnosis of multiple myeloma. Immunohistochemistry showed kappa light chain restriction suggestive of kappa associated gammopathy and serum free light chain ratio was increased.

 

 

Amyloidosis is often associated with deranged renal function in cases of multiple myeloma, due to light chain deposition in different organs. Few studies showed that bone scan plays an important role in the evaluation of amyloidosis, by demonstrating radiotracer uptake in the thyroid, tongue, salivary glands, nervous system, intestine, liver, spleen or kidney.1,2 The probable presence of amyloidosis with deranged renal function, in this case, provides a possible explanation for the abnormal distribution of radiotracer in lung and liver although histopathology was not done to confirm the presence of amyloidosis. 3

 

 

References

 

1.       Vakili Sadeghi M, Sedaghat S. Is 99m Tc-methylene diphosphonate bone scintigraphy a sensitive method for detecting bone lesions in multiple myeloma? Caspian J Intern Med. 2018 Spring;9:140-143.

2.       Wechalekar AD, Gillmore JD, Hawkins PN. Systemic amyloidosis. Lancet. 2016; 387: 2641-2654.

3.       Xu A, Lawton E, Smith S, Kalro A, Geake J. Pulmonary AL amyloidosis and multiple myeloma presenting as cough with diffuse pulmonary opacities. Respirol Case Rep. 2021; 9: e00786.

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