A 57-year-old male presents to your office complaining of fatigue and low energy. He also notes experiencing intermittent back pain that responds to ibuprofen. He has no significant past medical history. His family history is significant for his father dying of a heart attack at age 60. Fecal occult blood testing is negative. Laboratory studies reveal: Plasma protein electrophoresis reveals a high peak corresponding to gamma-globulins. The most likely diagnosis is:

Question

A 57-year-old male presents to your office complaining of fatigue and low energy.  He also notes experiencing intermittent back pain that responds to ibuprofen.  He has no significant past medical history.  His family history is significant for his father dying of a heart attack at age 60.  Fecal occult blood testing is negative.  Laboratory studies reveal:  Plasma protein electrophoresis reveals a high peak corresponding to gamma-globulins.  The most likely diagnosis is:

Quizplus · Accepted Answer

In multiple myeloma, neoplastic B-lymphocytes mature into plasma cells that synthesize abnormal (typically large) amounts of monoclonal immunoglobulin or immunoglobulin fragments (e.g. light chains). Clinical manifestations of multiple myeloma include impaired hematopoiesis leading to a normochromic, normocytic anemia and weakness; lytic bone lesions classically affecting the vertebral column and causing back pain and pathologic fractures; and hypercalcemia and AL amyloidosis, which contribute to renal dysfunction. Severe amyloidosis can also cause cardiac and cutaneous findings. The classic laboratory abnormalities in multiple myeloma include erythrocyte rouleaux formation on peripheral blood smear and Bence-Jones proteins in the urine. Serum protein electrophoresis (SPEP) is a more specific laboratory test used to determine if excessive monoclonal immunoglobulins are present in the serum. An "M peak" on SPEP indicates the presence of such an immunoglobulin. (An M peak may also be found in Waldenstrom macroglobulinemia and some lymphomas.) (Choices A and B) Iron deficiency can cause weakness due to a hypochromic, microcytic anemia and vitamin B12 (cobalamin) deficiency can cause weakness due to a macrocytic anemia. Vitamin B12 deficiency can also cause neurologic signs. (Choice C) CLL is a lymphocytic malignancy that may cause a normochromic, normocytic anemia, but immunoglobulin production is classically depressed, not increased, in CLL. (Choice D) Aplastic anemia would cause a uniform depression of all hematologic cell lines, including leukocytes and platelets. (Choice F) Hodgkin lymphoma is a B-cell malignancy characterized by the presence of Reed-Sternberg cells on lymph node histology. There may be anemia of chronic disease in patients with this condition, but a monoclonal gammopathy would not be expected. (Choice G) Patients with hypothyroidism may be anemic due to associated iron deficiency or pernicious anemia. However, monoclonal gammopathy would not be expected. Educational Objective: The finding of a high peak in the gamma-globulin region on serum protein electrophoresis (SPEP) usually represents an M protein consisting of an overproduced monoclonal immunoglobulin. Multiple myeloma causes an M protein peak on SPEP as well as anemia (weakness), lytic bone lesions (back pain, pathologic fractures), and renal insufficiency (related to amyloid deposition and hypercalcemia).

A 57-Year-Old Male Presents to Your Office Complaining of Fatigue