The ASCO Post is pleased to present Hematology Expert Review, an ongoing feature that quizzes readers on issues in hematology. In this installment, Drs. Abutalib and D’Souza explore the challenge of diagnosing and managing amyloidosis in a 70-year-old man with a history of hypertension, diabetes, hyperlipidemia, and atrial fibrillation.
Answers to Hematology Expert Review Questions here
A 70-year-old man is referred to your clinic for a consultation. Recently, a diagnosis of IgG monoclonal gammopathy of undetermined significance (MGUS) was established. Medical history is significant for essential hypertension, type II diabetes mellitus, hyperlipidemia, and atrial fibrillation. Review of systems is remarkable for grade II neuropathy of the feet, which has been stable for the past 2 years. Medications include aspirin, hydrochlorothiazide, metoprolol, apixaban, and subcutaneous insulin.
Physical examination is remarkable for an irregular heart rhythm, with a heart rate between 96 and 104 beats/min, blood pressure of 110/70 mm Hg, grade II systolic murmur, appreciable jugular vein distention, and 1+ bilateral pitting edema in the lower extremities. An electrocardiogram demonstrates low-voltage complexes. A two-dimensional echocardiogram detects an interventricular septum thickness of 16 mm (normal 6–10 mm), biatrial enlargement, and severe diastolic dysfunction (with preserved ejection fraction of 60%).
Complete blood cell count shows a hemoglobin level of 11.5 g/dL with a mean corpuscular volume of 84 fL and normal white blood cell and platelet counts. The creatinine clearance is 60 mL/min; corrected calcium is 10 mg/dL, with a normal liver function test. The serum M spike is 1.2 g/dL, with IgG kappa on immunofixation with an abnormal free light chain ratio of 4.69 (normal 0.26–1.65). The Congo red stain is negative on bone marrow biopsy, which has 9% kappa-restricted monoclonal plasma cells. However, it is positive on a subcutaneous fat aspirate (SFA). Skeletal imaging is unremarkable for a lytic lesion.
Syed A. Abutalib, MD Assistant Director, Hematology & Bone Marrow Transplantation Service, Cancer Treatment Centers of America, Zion, Illinois
Anita D’Souza, MD, MS Assistant Professor of Medicine, Division of Hematology/Oncology, Medical College of Wisconsin, Milwaukee
What is the best next step for this patient?
A. Plasma cell–directed therapy
B. Emergent cardiac catheterization
C. Determination of amyloid subtype
Which statement about this patient’s condition is correct?
A. Localized amyloidosis should be considered in the differential diagnosis.
B. Systemic amyloidosis should not be considered.
C. Amyloid subtyping is redundant in this scenario.
Which statement about mass spectrometry–based proteomic analysis is correct?
A. Mass spectrometry–based proteomic analysis can classify amyloidosis.
B. Mass spectrometry–based proteomic analysis needs a large sample.
C. Mass spectrometry–based proteomic analysis cannot be performed on a subcutaneous fat aspirate specimen.
If this patient has non-AL amyloid, what is the best management of the underlying plasma cell disorder?
A. Plasma cell–directed therapy
C. Annual bone marrow biopsy
Question 1: What is the next best step for this patient?
Correct Answer: C. Determination of amyloid subtype.
Amyloidosis encompasses a heterogeneous group of diseases bound by the characteristic deposition of amyloid fibrils in soft tissues and bone marrow, and it could be...