Multiple myeloma

Multiple myeloma
Updated: 09/04/2024
© Jun Wang, MD, PhD

General features
  • Plasma cell neoplasm
  • Clinical variants
Asymptomatic (smoldering) myeloma: NO related organ or tissue impairment
Non-secretory myeloma: NO M-protein by electrophoresis or immunofixation; clinical features similar to secretory myeloma except for low incidence of renal insufficiency and hypercalcemia
Plasma cell leukemia: Clonal plasma cells > 20% of the leukocyte differential count; aggressive disease
Clinical presentations
Key pathogenesis
  • DKK1 and FRP2: Inhibit Wnt, blocking bone formation
  • Elevated RANKL, promotes osteoclasts activity, similar to giant cell tumor of bone
  • Suppressed OPG
Key Laboratory findings
  • Monoclonal gammopathy (M spikes)
  • M proteins in serum or urine (Most common IgG, followed by IgA)
  • Bence Jones proteins in urine
  • Elevated immunoglobulin: > 3g/dl (IgG) or >2.5g/dl (IgA)
  • Rouleaux formation
  • Hypercalcemia
  • Abnormal renal functions
Key morphological features
  • Plasma cell infiltrate of marrow or other tissue
  • Abnormal plasma cells: Perinueclear clearing
  • Mott cells: Plasma cells with grapelike cytoplasmic inclusions (Russell bodies)
  • Russell bodies: Cytoplasmic cherry red refractive round bodies
  • Dutcher bodies: Intranuclear crystalline rods
 Markers
  • Positive: CD38, CD138, light chain restriction
  • Negative: CD19, CD20
Diagnostic criteria
  • A bone marrow aspirate or biopsy showing that at least 10 percent of the cells are plasma cells or the presence of a plasma cell tumor (called a plasmacytoma)
  • Plus at least one of the following two features:
Evidence of damage to the body as a result of the plasma cell growth, such as severe bone damage, kidney failure, anemia, or high calcium in the blood, and/or
Detection of one of the following findings: ≥60% plasma cells in the bone marrow; free light chain ratio of 100 or more (provided involved FLC level is at least 100 mg/L); or MRI showing more than one lesion (involving bone or bone marrow)
Genetic abnormalities
  • Various
  • IgH translocations
  • Myc, p53, RAS, RB1, etc
Negative prognosis indicator
  • Elevated IL-6: Promotes tumor cell survival
  • Hypercalcemia
  • Bence Jones proteinemia
  • Renal impairment
  • Translocation t(14;16), t(14;20), t(4;14) and deletion chromosome 17p (p53)

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Contents

Pathology notes Jun Wang, MD, PhD 1. General information Frequently discussed syndromes Terms of dermatology Terms of hematology 2. Primary immunodeficiency disorders 3. Hemodynamic abnormalities Shock Thrombosis and embolism Bleeding disorders 4.  Benign blood cell disorders Anemia Benign white cell disorders 5. Hematopoietic neoplasms Lymphoid neoplasms Myeloid neoplasms Histiocytic neoplasms: Langerhans cell histiocytosis 6. Cardiovascular system Pulmonary hypertension Cardiovascular system tumors 7. Respiratory tract tumors 8. Gastrointestinal tract Congenital disorders Infectious gastroenteritis Oral cavity Esophagus Stomach Intestinal tumors Salivary glands Exocrine pancreas and gallbladder 9. Urinary system Kidney masses Lower urinary tract 10. Male reproductive system 11. Female genital tract 12. Breast 13. Endocrine organs Pituitary gland Adrenal gland Thyroid gland Parathyroid gland Endocrine pancreas M
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Anemia

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Practice questions Anemia I

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Practice questions Anemia I © Jun Wang, MD, PhD   Abbreviations: Hb: hemoglobin HCT: hematocrit MCV: Mean Corpuscular Volume MCHC: Mean Corpuscular Hemoglobin RDW: Red Cell Distribution Width TIBC: total iron binding capacity   1. Use this case for the next three questions . A 25-year-old woman is brought to the emergency department 2 hours after being involved in a motor vehicle accident. She is conscious but feels dizziness and weakness.   Her blood pressure is 90/60 mmHg, and her heart rate is 120 beats per minute. Physical examination reveals pale skin and mucosa and a 15 cm laceration on her left thigh with significant bleeding. What are most likely the CBC and TIBC results? A. Low Hb, low HCT, high MCV, high RDW, high TIBC B. Low Hb, low HCT, slightly low MCV, normal RDW, normal TIBC C. Low Hb, low HCT, slightly high MCV, normal RDW, normal TIBC D. Normal Hb, normal HCT, normal MCV, normal
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