Caso Clinico

Clinical Chemistry 56:9 1390–1393 (2010)

Clinical Case Study

A Healthy Young Man Presenting with Multiple Rib Fractures
Lindsey Harle,1 Clayton Chan,2 Nadhipuram V. Bhagavan,3 Carlos N. Rios,1,4 Cheryl E. Sugiyama,4 Miki Loscalzo,4 Jane Uyehara-Lock,1,4 and Stacey A.A. Honda1,4*

CASE A 32-year-old, otherwise healthy man presented initially with right rib and sternal pain after lifting aheavy object. The patient also reported several rib fractures 1 year previously associated with coughing. On examination, the patient had bilateral rib tenderness. Chest x-ray revealed multiple healing fractures of the sixth, seventh, and eighth ribs. A bone scan demonstrated increased uptake in the sternum and bilaterally in the ribs. A complete blood count was normal with the exception of aplatelet count of 61 000/uL (reference interval, 130 000 – 440 000/uL). Alkaline phosphatase, creatinine, and calcium were within reference intervals. Total protein and albumin were 67 g/L (reference interval, 61–79 g/L) and 44 g/L (reference interval, 35– 48 g/L), respectively. Ig concentrations were decreased: IgG 6.07 g/L (reference interval, 7.51–15.60 g/L), IgA 0.31 g/L (reference interval, 0.69–2.09 g/L), and IgM 0.10 g/L (reference interval, 0.48 –2.74 g/L). We performed serum protein electrophoresis (SPEP)5 and immunofixation using the Sebia Hydrasys®. SPEP showed no monoclonal band in the region but an unexplained band in the region with a reduced -globulin concentration of 3.9 g/L (reference interval, 6 –14 g/L). Serum immunofixation electrophoresis showed a prominent monoclonalband in the region and hypogammaglobulinemia. Immunofixation studies for IgG, IgA, and IgM were negative for the presence of monoclonal bands. 2-Microglobulin was increased at 3.51 mg/L (reference interval, 1.85 mg/L). Twentyfour-hour urine collection was significant for a total protein of 0.54 g/24 h (reference interval, 0.15 g/24 h); urine protein electrophoresis (UPEP) and im-

QUESTIONS TOCONSIDER 1. List the significant and atypical findings in this case. 2. Given the patient’s SPEP and immunofixation results, what additional testing should be performed by the laboratory? 3. What is the differential diagnosis of a monoclonal band that shows staining for light chains, but not for IgG, IgA or IgM?

munofixation revealed 2 monoclonal bands.
PATIENT FOLLOW-UP

light chain

1Department of Pathology and 3 Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI; 2 Department of Oncology and 4 Department of Pathology, Kaiser Foundation Hospital, Honolulu, HI. * Address correspondence to this author at: Pathology/Regional Laboratory, Kaiser Foundation Hospital, 3288 Moanalua Road, Honolulu, HI 96819. E-mailstacey.honda@kp.org. Received August 4, 2009; accepted March 11, 2010. DOI: 10.1373/clinchem.2009.135095 5 Nonstandard abbreviations: SPEP, serum protein electrophoresis; UPEP, urine protein electrophoresis; ASCT, autologous stem cell transplantation.

A bone marrow biopsy revealed hypercellular marrow with markedly increased numbers of atypical plasma cells comprising 85% of the cell population.Chromosomal analysis demonstrated an abnormal karyotype with translocation between the long arms of chromosomes 11 and 14, suggestive of standard prognostic risk (1 ). Flow cytometry showed a monoclonal population of B lymphocytes with expression of surface IgD, light chain, plasma cell–associated antigen 1 (PCA-1), and CD38. Serum IgD was found to be 3.1 g/L (reference interval 0.18 g/L), and IgEconcentration was within reference intervals. The patient’s serum was sent to a reference laboratory for further workup for IgD and IgE immunofixation studies, which demonstrated an IgD monoclonal gammopathy migrating in the region. Based on the clinical and laboratory findings, we made the diagnosis of IgD multiple myeloma. The patient was initially treated with lenalidomide and dexamethasone....