Multiple Myeloma (MM)

Multiple myeloma (MM) is the most common plasma-cell malignancy (myeloma/plasma-cell myeloma/Kahler disease; described by Kahler 1889). Characterized by monoclonal plasma-cell proliferation secreting large monoclonal Ig. Incidence 2-3/100,000; M:F 1.6:1; age >40; Blacks 2x Whites.

Common Symptoms

Geographic bone defects; bone mass; cardiac amyloid deposition; bone destruction; osteoporosis; bone pain; proteinuria; diffuse osteoporosis; punched-out skull lesions

Causes and Pathogenesis

(1) Etiology: ionizing radiation, chronic antigenic stimulation, genetics, viruses, gene mutation. Survivors of atomic-bomb/radiation workers have higher risk (latency up to 15y). (2) Mechanism: arises from earlier hematopoietic precursor cell. Oncogene-related. IL-6 and other lymphokines/cytokines drive B→plasma-cell differentiation; anti-IL-6 trials ongoing. Osteolytic lesions: not direct erosion; tumor cells secrete IL-1, lymphotoxin, TNF, osteoclast-activating factor (OAF) → osteoclast activation → osteoporosis/bone destruction; chr6q deletion increases TNF/OAF; IFN-gamma/corticosteroids suppress. Clinical manifestations: bone-marrow suppression, infiltration (nodes/spleen/liver/airways), osteolytic lesions, hyperviscosity/coagulopathy, light-chain nephropathy/amyloidosis, suppressed normal Ig → infection. Gross: gray-red soft marrow-replacing tumor; expands cortex; spine cord compression. Microscopy: diffuse plasma cells; well-differentiated (mature plasma cells) vs poorly differentiated (histiocyte-like); binucleated/multinucleated forms; extramedullary infiltration (liver/spleen/nodes/kidney/lung/heart/thyroid/testis/ovary/GI/uterus/adrenal/subcutaneous); amyloid (light-chain) deposition in 8-15% (tongue/muscle/GI/kidney/myocardium/vessels/joints/skin).

Treatment

Drug, supportive, radiation therapy

Preventive Measures

Avoid radiation/chemical toxins; treat chronic disease; early screening; regular activity to prevent decalcification; oral/skin hygiene; prevent infection.

Department to Visit

It is recommended to visit the Hematology department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.