Multiple myeloma represents about 1% of all cancers and 10–20% of all hematologic malignancies. The clonal proliferation of malignant plasma cells in the bone marrow may result both in local growth and in systemic effects due to the overproduction of a monoclonal protein (M-protein). Plasma cell proliferation is linked to a variety of clinical presentations of the disease, ranging from simple monoclonal gammopathy of undetermined significance (MGUS) to smoldering myeloma (SMM), both not requiring any therapy, to full-blown “malignant” MM. Excess plasma cells in the bone marrow, M-protein, osteolytic bone lesions, renal disease, and immunodeficiency constitute the pathophysiologic basis of MM. Severe bone pain, pathologic fractures, spinal cord compression, and hypercalcemia are caused by lytic bone lesions. The clinical staging system for MM (International Staging System) is based on serum b 2-microglobulin and albumin levels. The PLUS system, a newer version of the Durie and Salmon system, has been recently released with the aim of improving the accuracy of staging by the use of advanced imaging modalities such as [18F]FDG-PET, [18F]FDG-PET/CT, and MRI. For staging, detection of osteolytic lesions is generally based on conventional planar bone X-rays. If skeletal X-ray survey is negative and clinical symptoms are present, CT or MRI has been used to increase the sensitivity and specificity. CT can be considered as the ideal diagnostic investigation for identifying early bone destruction and extramedullary lesions. CT is useful for guiding biopsy and for planning surgical and radiation therapy, while it can also identify long bones (femora and humeri) at risk of fracture. MRI is the method of choice for evaluating bone marrow involvement, based on the loss of the fatty bone marrow component due to replacement by plasma cells. Bone scintigraphy with 99mTc-labeled disphosphonate is not useful for diagnosis nor for staging of MM, as the sensitivity for detecting bone lesions is low. Therefore, non specific oncotropic radiopharmaecuticals have been extensively studied such as 99mTc-sestamibi. [18F]FDG is the standard for radionuclide imaging in patients with MM, showing a focal or diffuse pattern of uptake reflecting the distribution of bone marrow disease. However, patients with MGUS generally have a negative [18F]FDG-PET scan. Leukemia is a cancer of the bone marrow and blood accounting for 2.5% of all cancers and 30.4% of all hematologic malignancies. Leukemias are the most common pediatric tumor. Clinical manifestations at presentation include fevers, night sweats, weight loss, easy bruising or bleeding, dyspnea, dizziness, and infections (particularly frequent in childhood). Extremity and joint pain may be the first presenting symptom and occurs up to 1/3 of childhood presentation. Less than 10% of patients have symptomatic central nervous system (CNS) involvement. Morphology and cytochemical stains are essential in the initial workup. The bone marrow is usually hypercellular and replaced with a homogenous population of leukemic blasts. Leukemia is not staged like most other cancers because leukemia involves the marrow of most bones and leukemic cells circulate throughout the bloodstream to all parts of the body. Bone scintigraphy may be helpful to elucidate the etiology of bone pain in children demonstrating abnormalities in the majority of leukemic patients with bone lesions. Skeletal X-ray may be also used to detect leukemic changes in bone or joint in presence of bone pain. Ultrasound and CT scan are generally used to assess extramedullary involvement in the abdomen, and brain MRI is indicated to assess the CNS abnormalities due to the leukemia. In case of the transformation of chronic lymphocytic leukemia cells into aggressive type of lymphoma, [18F]FDG-PET and [18F]FDG-PET/CT are considered the method of choice for early assessment.
- Bone cancer imaging
- Hematologic malignancies in imaging
- Multiple myeloma
ASJC Scopus subject areas