IgG4-Related Plasmacytosis

Lessons From the Friday Unknowns

The patient is an 75 year-old woman with history of shortness of breath. PET CT showed a mass-like consolidation in the right lower lobe and enlarged lymph nodes in the mediastinum and prominent lymph nodes in the abdomen and pelvis, suspicious for lymphoproliferative disorder. He was also found to have hypercalcemia, elevated protein gap, and elevated kappa/lambda ratio, concerning for possible multiple myeloma. Recent SPEP showed increased in IgG4 (1710) and IgG (6639), gamma globulin, free kappa and lambda light chains. No…