A 59-year-old man comes to the office due to 3 months of progressive fatigue and back pain. The back pain occurs mainly with movement or positional changes. Physical examination reveals midline tenderness over the middle and lower back. Laboratory evaluation shows a hemoglobin level of 10.2 g/dL and serum calcium level of 12 mg/dL. A bone marrow aspirate is performed, and the histopathologic findings are shown below. This patient is at greatest risk for developing which of the following conditions?

Question

A 59-year-old man comes to the office due to 3 months of progressive fatigue and back pain.  The back pain occurs mainly with movement or positional changes.  Physical examination reveals midline tenderness over the middle and lower back.  Laboratory evaluation shows a hemoglobin level of 10.2 g/dL and serum calcium level of 12 mg/dL.  A bone marrow aspirate is performed, and the histopathologic findings are shown below.  This patient is at greatest risk for developing which of the following conditions?

Quizplus · Accepted Answer

11ec160b_3988_f19a_9249_c537845d95d9_MD0001_00 This patient's bone marrow aspirate shows numerous plasma cells, which can be identified by abundant basophilic cytoplasm, eccentric nuclei, well-developed Golgi apparatus (perinuclear paleness), and "clock-face" (peripheral) chromatin. A bone marrow sample with >10% plasma cells is strongly suggestive of multiple myeloma (MM), a clonal plasma cell malignancy. In MM, neoplastic plasma cells: Replicate in the bone marrow and choke out normal hematopoiesis, leading to normocytic, normochromic anemia (impaired erythropoiesis) and increased risk of infection (impaired B-cell lymphopoiesis). Secrete osteolytic cytokines, leading to bone pain, osteolytic (radiolucent) bone lesions, and hypercalcemia. Produce large quantities of monoclonal immunoglobulin (paraprotein) composed of heavy and light chains (eg, IgG, IgA) or light chains alone. Light chains can deposit in the renal tubules, leading to light-chain cast nephropathy, which is usually characterized by mild renal insufficiency and waxy, laminated urinary casts (Bence Jones). Light chains can also form insoluble fibrils and deposit in major organs, leading to amyloid light-chain amyloidosis. This can contribute to the already elevated risk of renal failure as well as heart failure and neurologic dysfunction. Amyloidosis can often be identified on biopsy using hematoxylin and eosin stain (eosinophilic extracellular deposits) or Congo red stain viewed under polarized light (apple-green birefringence). (Choice B) Cardiac tamponade can be associated with some neoplasms (eg, lung, breast) due to tumor invasion of the pericardium. MM does not typically cause pericardial disease; therefore, it is not associated with cardiac tamponade. (Choice C) Hepatic failure is most often linked to viral hepatitis or chronic alcohol use. It occasionally occurs due to malignant infiltration of the liver (eg, lymphoma, breast cancer); however, risk of hepatic failure with MM is low; amyloidosis is a far more common complication. (Choice D) Hyperthyroidism is most often due to Graves disease, an autoimmune disorder that generates TSH-receptor antibodies. It can also be seen with medications (eg, lithium) and tumors that produce TSH (eg, pituitary adenoma). MM is not linked to hyperthyroidism. (Choice E) Meningeal carcinomatosis is a rare condition associated with some solid tumors (eg, breast cancer, lung cancer, melanoma). Tumor spread to the leptomeninges can cause mass effect (eg, headache, hydrocephalus), cranial/spinal nerve dysfunction, and focal neurologic issues. MM does not typically spread to the leptomeninges. (Choice F) Atraumatic splenic rupture can occur with leukemia and lymphoma due to massive splenomegaly from extramedullary hematopoiesis and/or underlying tumor infiltration. MM does not typically cause significant extramedullary hematopoiesis and usually replicates in the bone marrow, not the spleen. Educational objective: Amyloid light-chain amyloidosis is associated with multiple myeloma and other monoclonal plasma cell dyscrasias due to the deposition of insoluble immunoglobulin light-chain fibrils in major organs (eg, kidneys, heart, neurologic system). A bone marrow sample with >10% plasma cells is strongly suggestive of multiple myeloma.

A 59-Year-Old Man Comes to the Office Due to 3