IPLab:Lab 6:Multiple Myeloma

Clinical Summary

This 63-year-old female presented with the complaint of left chest pain of approximately 4 months duration. Physical examination revealed that the pain was along the distribution of the left sixth intercostal nerve. Chest film showed a posterior mediastinal mass with partial collapse of T6. A lytic lesion of the right distal clavicle was noted on subsequent radiological examination. A bone scan revealed increased uptake in thoracic vertebrae. Serum alkaline phosphatase was elevated slightly (143 U/L). Serum protein electrophoresis was normal, while urine protein electrophoresis showed a monoclonal spike in the Gamma region. A bone marrow study was non-diagnostic.

Autopsy Findings

A thoracotomy was performed after an unsuccessful needle biopsy. At thoracotomy, a 3-cm posterior mediastinal mass was identified that extended to within 1-2 mm of the aorta and into the interspace between the ribs.

Images

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  This is a low-power photomicrograph of the mediastinal mass. The mass is encapsulated and contains cellular areas (blue) and areas of pale red material.
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  This higher-power photomicrograph shows the junction between an amorphous hyaline-appearing area (amyloid) on the right and cellular areas (plasmacytoid cells) on the left.
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  This high-power photomicrograph demonstrates the cells that make up this tissue. These cells resemble plasma cells and are the malignant cell of multiple myeloma.
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  This is a photograph of the vertebral column from this patient at autopsy. Notice the collapsed vertebra (1). There are multiple variably-sized white nodules (2) within the bone marrow. These are accumulations of malignant plasma cells in this case of multiple myeloma.

Study Questions

• What class of amyloid is this?

AL - Immunocyte dyscrasias - primary amyloidosis.

• What is the chemical nature of this type of amyloid?

Immunoglobulin light chains, usually lambda.

• What is the usual organ distribution of amyloid in this class of amyloidosis?

Heart, gastrointestinal tract, peripheral nerves, skin, and tongue.

Malignant bone lesions are part of the differential for increased uptake of isotope during a bone scan.

A normal alk-phos level is 39 to 117 U/L.

A thoracotomy is a surgical procedure in which an opening is made in the chest wall.