Prepared by Ankur Bant, MD, Resident, Internal Medicine/Pediatrics, Richard Carlson, MD, PhD, Director of Intensive Care Unit, Chandra Jha, MD, Director of Hematology/Oncology, Derrick Aipoalani, DO, Chief Resident, and Marko Markov, MD, Resident, Internal Medicine, Maricopa Integrated Health System, Phoenix, Ariz
A 35-year-old Hispanic man with no significant medical history presented complaining of malaise, fever, and a nontender, enlarging right axillary mass of 2 months' duration (Figure). Laboratory test results were: platelet count, 54 x 109/L; hemoglobin, 99 g/L; and normal serum calcium and creatinine levels. Serum protein electrophoresis with immunofixation revealed elevations in gamma globulins (2.11 g/dL), immunoglobulin G (2150 mg/dL), and kappa chains (2110 mg/dL). A biopsy of the
right axillary mass showed monoclonal plasma cells staining for clusters of differentiation (CD) markers CD138 and CD79A.
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What's Your Diagnosis?
- B-cell lymphoma
- Extramedullary plasmacytoma
- Plasmablastic lymphoma
- Multiple myeloma
Quiz Answer
Extramedullary plasmacytoma?This rare plasma-cell tumor originates as a soft-tissue lesion, without osseous or systemic involvement. Diagnosis requires a histologically confirmed single lesion showing monoclonal plasma cells and the exclusion of multiple myeloma.1 The mainstay of treatment is tumoricidal radiation at a dosage of 40 to 50 Gy over 4 to 5 weeks.2 Adjuvant chemotherapy has no proven benefit. However, thalidomide (Thalomid) has been used as palliative therapy in cases that are refractory to standard treatment or that have progressed to multiple myeloma.2
Extramedullary plasmacytoma, especially the anaplastic variety, can progress to multiple myeloma.1,2 Therefore, it is important to exclude the presence of multiple myeloma before initiating radiation therapy. In our patient, multiple myeloma was excluded by the absence of bone marrow plasmacytosis, hypercalcemia, renal failure, and bony involvement, and the presence of only a single lesion in the axilla.
There were no B-cell markers, ruling out cutaneous B-cell lymphoma. Our patient's clinical presentation was not typical of plasmablastic lymphoma, since he had no oral lesions and no signs of infection with Epstein-Barr virus, human herpesvirus 8, or HIV.3
References
- Mendenhall WM, Mendenhall CM, Mendenhall NP. Solitary plasmacytoma of bone and soft tissues. Am J Otolaryngol. 2003;24:395-399.
- Soutar R, Lucraft H, Jackson G, et al. Guidelines on the diagnosis and management of solitary plasmacytoma of bone and solitary extramedullary plasmacytoma. Clin Oncol (R Coll Radiol). 2004;16:405-413.
- Colomo L, Loong F, Rives S, et al. Diffuse large B-cell lymphomas with plasmablastic differentiation represent a heterogeneous group of disease entities. Am J Surg Pathol. 2004;28:736-747.